Mr. Adams’s police credentials have helped him rise to the top of this year’s mayoral field. But his relationship with the department is complex.As Eric Adams lined up for graduation at the New York City Police Academy in 1984, he congratulated the cadet who had beaten him out for valedictorian, only to learn that the other recruit’s average was a point lower than his own. Mr. Adams complained to his commander about the slight.“Welcome to the Police Department,” Mr. Adams recalled the senior officer telling him. “Don’t make waves.”“Man, little do you know,” Mr. Adams remembered thinking. “I’m going to make oceans.”Over the course of the two-decade Police Department career that followed, Mr. Adams troubled the water often. He was a fierce advocate for Black officers, infuriating his superiors with news conferences and public demands. As he rose through the ranks to captain, he spoke out against police brutality, and, later, the department’s stop-and-frisk tactics.His uncommon willingness to criticize the police openly may have stalled his ascent. But many who knew him then said Mr. Adams had already set his sights on a grander goal anyway: public office.Mr. Adams’s outspokenness inspired admiration among many of the Black officers he championed. But his penchant for self-promotion and his blunt-force ambition — he ran for Congress at 33, only a decade into his police career — rankled others in law enforcement, who thought he was using the Police Department as a steppingstone.Today, Mr. Adams, now 60 and the borough president of Brooklyn, is the Democratic front-runner in the New York City mayor’s race, mounting a campaign that leans hard on his time as an officer. But interviews with friends, mentors, former colleagues and political rivals show that his relationship to the police has always been complicated.A year after protests against police brutality and racism shook the city, Mr. Adams has sought to appeal to voters as a reformer who spent 22 years trying to fix what he says was a broken department before retiring to run for State Senate in 2006. But during his bid for mayor he has also positioned himself as the candidate whose law enforcement experience makes him the best choice for ensuring the safety of a fearful electorate as violent crime rises in the city.Mr. Adams’s attempt to manage that precarious balance has drawn attacks from rivals. He has been criticized from the left over his qualified support of the stop-and-frisk strategy, which he fought as an officer but calls a useful tool that previous mayoral administrations abused. And he has struggled to explain how the one-time internal critic of the department is now running as the tough-on-crime ex-cop.“I don’t hate police departments — I hate abusive policing, and that’s what people mix up,” Mr. Adams said in an interview with The New York Times. “When you love something, you’re going to critique it and make it what it ought to be, and not just go along and allow it to continue to be disruptive.”But the apparent tension between Mr. Adams’s past and present public lives can be difficult to reconcile. He has spoken of wearing a bulletproof vest, defended carrying a gun and argued against the movement to defund the police. Yet for most of his life he has harbored deep ambivalence about policing, and his time in the department was more notable for high-profile, often provocative advocacy than it was for making arrests or patrolling a beat.His broadsides sometimes overreached, his critics said, while some of his actions and associations landed him under departmental investigation. Wilbur Chapman, who is also Black and was the Police Department’s chief of patrol during Mr. Adams’s time on the force, said Mr. Adams’s critiques lacked substance and impact.“There was nothing credible that came out of them,” Mr. Chapman said. “Eric had used the Police Department for political gain. He wasn’t interested in improving the Police Department.”A Marked ManMr. Adams as a police lieutenant at age 32. He was outspoken from his earliest days in the department.Ruby Washington/The New York TimesThe seed of Mr. Adams’s law enforcement career took root when he was 16. Randolph Evans, a Black teenager, had been shot and killed by the police in Brooklyn’s East New York section on Thanksgiving Day in 1976. The officer responsible was found not guilty by reason of insanity.A spate of police killings of Black youth in New York spawned an activist movement led by the Rev. Herbert Daughtry, who founded the National Black United Front. Mr. Adams, who had his own share of run-ins with the police while growing up in Brooklyn and Queens, became one of the movement’s young stewards.As a teenager, he said, he realized that the police viewed him and other young Black males as threats to public order. According to a story he has often told, Mr. Adams and his brother were beaten in the 103rd Precinct station house in Queens when he was just 15.Amid the police killings, Mr. Daughtry urged a group that included Mr. Adams to join the Police Department. Mr. Daughtry, in an interview, said that pushing Black men to enlist in what was effectively a hostile army was anathema to some. But he envisioned a two-pronged approach.“Some of us needed to work outside of the system, and some inside the system,” Mr. Daughtry said. “To model what policemen should be about and to find out what’s going on. Why were we having all these killings?”For Mr. Adams, becoming a policeman was an act of subversion. Still angry over the beating, he saw “an opportunity to go in and just aggravate people,” he told Liz H. Strong, an oral historian at Columbia University, in a 2015 interview for a collection of reminiscences of retired members of the Guardians Association, a fraternal organization of Black police officers.He wasted no time. In October 1984, a police sergeant fatally shot Eleanor Bumpurs, a disabled, mentally ill Black woman, in the chest. When a chief tried to explain why the shooting was justified, Mr. Adams, who was still in the academy, disagreed forcefully, saying a white woman would not have been killed that way. Higher-ups took note of his attitude.“There was a signal that went out: ‘Keep an eye on this guy,’” said David C. Banks, a friend of Mr. Adams’s whose father and brother were influential figures in the Police Department. “He did it before he was officially on the job, so he was already a marked man.”‘A Driven, Motivated Cat’Mr. Adams, right, was a fixture at press events as a leader of 100 Blacks in Law Enforcement Who Care. James Estrin/The New York TimesMr. Adams began as a transit police officer, patrolling the subway or in a radio car, later using his associate degree in data processing to work on the department’s computer programs that tracked crime. In 1995, he became a member of the Police Department after the transit police was absorbed by the bigger agency.On the force, he was not known as a dynamic, run-and-gun street cop.“I wouldn’t say Eric was an aggressive cop, but he was competent,” said David Tarquini, who worked in the same command.Randolph Blenman, who patrolled with Mr. Adams when both were transit officers, called him “a thinking man’s officer,” whether they were arresting someone or helping them. “He always did his best to get his point across without losing his composure,” Mr. Blenman said.Mr. Adams moved up the ranks by taking tests, rising first to sergeant, then to lieutenant, and eventually to captain. But any further promotions would have been discretionary, and perhaps unavailable to Mr. Adams because of his outspokenness.Instead, Mr. Adams quickly became well-known for his activism. He signed up with the Guardians upon joining the force, and ultimately became its leader.Another officer, Caudieu Cook, recalled Mr. Adams working out with him and other young Black officers at a Brooklyn gym in the late 1980s and early 1990s. Mr. Cook said he was focused on getting in shape, while Mr. Adams spoke of his vision for the department and the city. His story of being beaten by the police as a child resonated with the others. Unlike him, they feared retaliation if they spoke out.“You have to be very careful when you speak out against injustices because you could get ostracized,” Mr. Cook said. Mr. Adams, he said, “was just a driven, motivated cat.”Mr. Adams focused on discrimination in policing, and within the department itself. He warned in the 1990s that rising arrests of teenagers for low-level offenses would backfire in the long run, and he said Black and Hispanic New Yorkers would bear the brunt of ticket quotas.He also spoke out often against the racism that Black officers encountered, including the fear many of them felt of being mistaken for criminals when not in uniform.A decade after entering the department, Mr. Adams made his first attempt to leave it, waging a congressional primary race against Representative Major Owens, a Democrat, in 1994. His campaign did not gain traction, and he remained an officer..css-1xzcza9{list-style-type:disc;padding-inline-start:1em;}.css-3btd0c{font-family:nyt-franklin,helvetica,arial,sans-serif;font-size:1rem;line-height:1.375rem;color:#333;margin-bottom:0.78125rem;}@media (min-width:740px){.css-3btd0c{font-size:1.0625rem;line-height:1.5rem;margin-bottom:0.9375rem;}}.css-3btd0c strong{font-weight:600;}.css-3btd0c em{font-style:italic;}.css-w739ur{margin:0 auto 5px;font-family:nyt-franklin,helvetica,arial,sans-serif;font-weight:700;font-size:1.125rem;line-height:1.3125rem;color:#121212;}#NYT_BELOW_MAIN_CONTENT_REGION .css-w739ur{font-family:nyt-cheltenham,georgia,’times new roman’,times,serif;font-weight:700;font-size:1.375rem;line-height:1.625rem;}@media (min-width:740px){#NYT_BELOW_MAIN_CONTENT_REGION .css-w739ur{font-size:1.6875rem;line-height:1.875rem;}}@media (min-width:740px){.css-w739ur{font-size:1.25rem;line-height:1.4375rem;}}.css-9s9ecg{margin-bottom:15px;}.css-uf1ume{display:-webkit-box;display:-webkit-flex;display:-ms-flexbox;display:flex;-webkit-box-pack:justify;-webkit-justify-content:space-between;-ms-flex-pack:justify;justify-content:space-between;}.css-wxi1cx{display:-webkit-box;display:-webkit-flex;display:-ms-flexbox;display:flex;-webkit-flex-direction:column;-ms-flex-direction:column;flex-direction:column;-webkit-align-self:flex-end;-ms-flex-item-align:end;align-self:flex-end;}.css-12vbvwq{background-color:white;border:1px solid #e2e2e2;width:calc(100% – 40px);max-width:600px;margin:1.5rem auto 1.9rem;padding:15px;box-sizing:border-box;}@media (min-width:740px){.css-12vbvwq{padding:20px;width:100%;}}.css-12vbvwq:focus{outline:1px solid #e2e2e2;}#NYT_BELOW_MAIN_CONTENT_REGION .css-12vbvwq{border:none;padding:10px 0 0;border-top:2px solid #121212;}.css-12vbvwq[data-truncated] .css-rdoyk0{-webkit-transform:rotate(0deg);-ms-transform:rotate(0deg);transform:rotate(0deg);}.css-12vbvwq[data-truncated] .css-eb027h{max-height:300px;overflow:hidden;-webkit-transition:none;transition:none;}.css-12vbvwq[data-truncated] .css-5gimkt:after{content:’See more’;}.css-12vbvwq[data-truncated] .css-6mllg9{opacity:1;}.css-qjk116{margin:0 auto;overflow:hidden;}.css-qjk116 strong{font-weight:700;}.css-qjk116 em{font-style:italic;}.css-qjk116 a{color:#326891;-webkit-text-decoration:underline;text-decoration:underline;text-underline-offset:1px;-webkit-text-decoration-thickness:1px;text-decoration-thickness:1px;-webkit-text-decoration-color:#326891;text-decoration-color:#326891;}.css-qjk116 a:visited{color:#326891;-webkit-text-decoration-color:#326891;text-decoration-color:#326891;}.css-qjk116 a:hover{-webkit-text-decoration:none;text-decoration:none;}In 1995, Mr. Adams and others formed 100 Blacks in Law Enforcement Who Care. They felt that without the departmental recognition that the Guardians had, they could better pursue their own agenda: advocating internally for racial justice while providing community grants and advice to the public.Four years later, officers from the department’s Street Crimes Unit killed a man named Amadou Diallo in a hail of bullets in the Bronx. Mr. Adams began to highlight the unit’s excessive use of stop-and-frisk, a crime-control tactic that a federal judge would find had devolved into racial profiling.Mr. Adams conceived of a plan to use Yvette Walton, a Black officer who had served in the unit, to make the case. Soon after the shooting, Mr. Adams appeared at a news conference with Ms. Walton, who was disguised because she was not allowed to speak publicly about police issues.He also appeared with Ms. Walton, again in disguise, at a City Council hearing. Within an hour of the hearing, Ms. Walton was identified and fired, supposedly for abusing the department’s sick leave policies.‘Just fighting’In 1999, Mr. Adams, second from right, appeared with a disguised officer from the Street Crimes Unit, helping to shed a light on the department’s racially biased stop-and-frisk tactics. Librado Romero/The New York TimesThe disguising of Ms. Walton was only one of Mr. Adams’s media-enticing innovations. Another was a report card that graded the department on issues of racial equality.Paul Browne, the spokesman for Ray Kelly, the police commissioner at the time, said Mr. Adams approached him around 2002 to let him know that Mr. Kelly’s administration could get high marks if it promoted candidates that Mr. Adams recommended.“If we played ball with his requests, the report cards would reflect it,” Mr. Browne said. But the department’s leaders remained overwhelmingly white, and the report card grades were poor.The perception among higher-ups that Mr. Adams’s tactics were more self-serving than authentic began early on. Mr. Chapman, the former chief of patrol, said that he asked Mr. Adams in 1993 whether the Guardians would participate in a minority recruitment drive. Mr. Chapman said Mr. Adams declined.“It’s easy to be angry,” Mr. Chapman said. “But anger doesn’t translate into constructive change, and that’s what I was looking for.”Mr. Adams said in the interview with The Times that the criticisms from Mr. Browne and Mr. Chapman were “not rooted in facts.” He said that his groups were major recruiters of Black officers, and that it would be silly to attack one’s superiors for personal gain.“Who in their right mind for self-promotion would go into an agency where people carry guns, determine your salary, your livelihood, and just critique them?” Mr. Adams said. “Unless you really believe in what you are doing.”As he skewered the Police Department, Mr. Adams was also investigated four times by it.Investigators examined his relationships with the boxer Mike Tyson, who was convicted of rape in 1992, and Omowale Clay, a Black activist who had been convicted of federal firearms violations. Police officers are forbidden from knowingly associating with people involved in crime.The department also investigated a Black police officer’s report that Mr. Adams and others in 100 Blacks had harassed him. Investigators could not prove Mr. Adams violated department rules.Mr. Adams and the group sued the department, accusing it of violating their civil rights by using wiretaps during the Clay and the harassment investigations. The suit was dismissed by a judge who called the wiretapping accusations “baseless.” (The department had obtained telephone records.)“You do an analysis of my Internal Affairs Bureau investigations, you’ll see they all come out with the same thing,” Mr. Adams said. “Eric did nothing wrong.”In October 2005, Mr. Adams gave a television interview in which he accused the department of timing an announcement about a terrorist threat to give Mayor Michael R. Bloomberg an excuse to skip an election debate. Speaking to The Times, Mr. Adams said the department had not deployed officers to deal with the threat as officials claimed.He was brought up on disciplinary charges, and a Police Department tribunal found him guilty of speaking for the department without authorization. Mr. Kelly docked Mr. Adams 15 days of vacation pay. Mr. Adams retired, ran for State Senate and won.“When I put in to retire, they all of a sudden served me with department charges,” Mr. Adams said in his oral history interview. “It was a good way to leave the department. Leaving it the way I came in: Just fighting.”J. David Goodman More