The only politician ever to beat Barack Obama will retire from the US Congress at the end of the year.

Bobby Rush, a Democratic representative from Illinois, faced Obama in a House primary in 2000 – and beat him by more than 30 points. Obama went on to win a US Senate seat in 2004 and become America’s first Black president five years later.

Rush said Obama, then 38, “was blinded by his ambition” and moved too soon, against the wrong target. Obama said he had his “rear end handed to me”.

Rush, 75 and first elected to Congress in 1992, is a minister and social activist who co-founded the Illinois Black Panther party and was described by Politico on Monday as “a legend in Chicago politics”.

In a video, he said: “I have been reassigned. Actually, I’m not retiring, I’m returning home. I’m returning to my church. I’m returning to my family. I have grandchildren. I’m returning to my passion.

“I will be in public life. I will be working hand in hand with someone who will replace me.”

Rush’s district is solidly Democratic but political rune-readers still found worrying signs for the national party. Rush is the 24th Democrat to announce that they will not run in 2022. Only 11 Republicans have said the same.

Two of those, Adam Kinzinger of Illinois and Anthony Gonzalez of Ohio, voted to impeach Donald Trump over the Capitol riot and subsequently concluded they had no place in a party he dominates.

Republicans are favored to take back the House in November – despite their supporters having physically attacked it, in an attempt to overturn the presidential election, on 6 January last year.

Rush made headlines during his time in Congress. In 2012, after the shooting death in Florida of the Black teenager Trayvon Martin, he showed solidarity by wearing a hooded sweatshirt on the House floor.

“Racial profiling has to stop,” he said. “Just because someone wears a hoodie does not make them a hoodlum.”

It earned Rush a reprimand for violating rules regarding wearing hats in the chamber.

Martin’s father, Tracy Martin, praised Rush and told the Washington Post: “This is something that needs to be talked about … This is a country of freedom of speech.”

Rush could raise eyebrows with sharp comments, as when he dismissed an anti-violence plan by an Illinois Republican senator, Mark Kirk, as a simplistic “white boy” solution to a complex problem.

He also pushed legislation designating lynching as a hate crime, named for Emmett Till, a Black Chicago teen whose killing in 1955 fueled the civil rights movement.

Born in Georgia, Rush served in the US army and became involved in civil rights campaigning. In 1969, he was arrested and convicted on a weapons charge.

In his video on Tuesday, he said: “My faith tells me that there’s a reason I’m still here. By all rights, I should have been murdered on 5 December 1969, the day after the police assassinated [the Black Panthers leader] Fred Hampton.

“They came for me the next day, shot down my door, but by the grace of God my family and I were not home.”

Elected as a Chicago alderman, he made an unsuccessful bid for mayor before entering Congress. Just before the 2000 primary against Obama, one of Rush’s sons was shot dead. Rush subsequently focused on gun control.

He is also a cancer survivor.

“I am not leaving the battlefield,” he said. “I am going to be an activist as long as I’m here in the land of the living, and I will be making my voice heard in the public realm – from the pulpit, in the community, and in the halls of power.”