Carl Levin, a Democrat who was the longest-serving US senator from Michigan and who prominently opposed the rush to war in Iraq, has died. He was 87.

Levin had a slightly rumpled, down-to-earth demeanor throughout a 36-year career in which he was a staunch supporter of his hometown auto industry. The Harvard-educated attorney also was a respected leader of the Senate armed services committee.

The former taxi driver and auto-line worker, who for decades kept a faded 1953 union card in his wallet, died on Thursday. His family and the Levin Center at Wayne State University law school did not release a cause of death. He had been living with lung cancer.

“We are all devastated by his loss. But we are filled with gratitude for all of the support that Carl received throughout his extraordinary life and career, enabling him to touch so many people and accomplish so much good,” the statement said.

Elected to the Senate in 1978, Levin targeted tax shelters, supported manufacturing jobs and pushed for military funding.

“He’s just a very decent person,” Democratic senator Jack Reed of Rhode Island said in 2008. “He’s unpretentious, unassuming. He never forgets that what we’re doing is enmeshed with the lives of the people he represents.”

Levin worked effectively with Republicans. But he was in the minority when he voted against sending troops to Iraq in 2002, and two years later he said George W Bush’s administration had “written the book on how to mismanage a war”.

He gave a cautious endorsement to Barack Obama’s 2009 buildup of troops in Afghanistan, but later warned of “fraying” Democratic support.

He was critical of Ronald Reagan’s buildup of nuclear weapons, saying it came at the expense of conventional weapons needed to maintain military readiness.

Joe Biden, who sat with Levin in the Senate for 30 years, said on Friday “he was one of the most honorable and decent people I have ever known.” Levin, he said, was “brilliant, humble and principled”, embodying “the best of who we are as Americans”.

In 2006, Time magazine said: “No one would accuse Carl Levin of looking like Hollywood’s version of a US senator. He’s pudgy, balding and occasionally rumpled, and he constantly wears his glasses at the very tip of his nose. Still, the Michigan Democrat has gained respect from both parties for his attention to detail and deep knowledge of policy, especially in his role as a vigilant monitor of businesses and federal agencies.”

Levin led an investigation in 2002 into Enron, which declared bankruptcy amid financial scandal. The investigation contributed to a federal law that requires executives to sign off on financial statements so they can be criminally liable for phony numbers.

Levin pushed legislation designed to crack down on offshore tax havens, which he said cost the US at least $100bn a year. He was an advocate for stem cell research and gun control.

Levin supported giving $25bn in loan guarantees to General Motors and Chrysler, arguing that a vibrant domestic auto industry was crucial to rebuilding the economy after the 2008 recession. He also was a member of a task force supporting efforts to fight pollution and other problems affecting the Great Lakes.

“If you’ve ever worn the uniform, worked a shift on an assembly line, or sacrificed to make ends meet, then you’ve had a voice and a vote in Senator Carl Levin,” Obama said in 2013. “No one has worked harder to bring manufacturing jobs back to our shores, close unfair tax loopholes and ensure that everyone plays by the same set of rules.”

Levin was born in Detroit on on 28 June 1934. He earned a bachelor’s degree in political science from Swarthmore College in 1956 and a law degree from Harvard in 1959. He married Barbara two years later and they raised three daughters.

He was Michigan’s only Jewish senator. But he once said public service was in his DNA, and politics often was discussed at the dinner table when he was a boy.

His older brother, Sandy Levin, became a congressman with a liberal voting record. Their father was on the Michigan Corrections Commission. In 1964, Levin was named an assistant state attorney general and the first general counsel for the Michigan Civil Rights Commission. Detroit voters elected him to the city council in 1969. In 1978 he beat a Republican to win a Senate race. He won the seat five more times.

Democratic governor Gretchen Whitmer called Levin a “champion for Michigan”.

“He saw what we were capable of when we came to the table as Michiganders, as Americans, to get things done,“ she said. “Carl devoted his life to public service, and it us up to us to follow his example.”

After retirement, the Levin Center at Wayne Law was established to promote fact-based, bipartisan oversight and to encourage civil dialogue. He chaired the center and co-taught courses. He also was a partner at the Honigman law firm in Detroit. His memoir, Getting to the Heart of the Matter, was published in March. The Navy named a destroyer for him.

His nephew, Andy Levin, was reelected in 2020 to his father’s congressional seat in suburban Detroit.

“Carl Levin personified integrity and the notion of putting the public good above self-interest,” Andy Levin said, calling him “the very picture of sober purpose and rectitude. In truth, he wasn’t un-fun. In fact, he often pierced tense situations with self-deprecating humor, and he privately shared incisive observations about others with staff and colleagues.”