LOS ANGELES — The civil rights leader Bayard Rustin, whose legacy had been tarnished by a 1953 conviction under laws that targeted L.G.B.T.Q. people, was posthumously pardoned by Gov. Gavin Newsom of California on Tuesday.

State lawmakers who lobbied for the pardon had called those old laws unjust tools of oppression. Governor Newsom also announced a process that would allow anyone convicted under the laws to seek clemency.

Mr. Rustin, who died in 1987 at age 75, worked alongside Martin Luther King Jr. for decades. He was a planner of the Montgomery bus boycott and the primary architect of the March on Washington in 1963. But other leaders distanced themselves publicly because he was gay.

The pardon overturned a 1953 criminal conviction. Mr. Rustin spent 50 days in Los Angeles County jail and was registered as a sex offender after being discovered having sex in a parked car in Pasadena, Calif.