John Ridley’s Oscar win for adapted script for “12 Years a Slave” culminates more than two decades in Hollywood for the Milwaukee-born writer.

Ridley began his thank-yous by singling out a sitcom script supervisor when he started in Hollywood, “Mr. Brad Pitt” and producer Jeremy Kleiner. It was Ridley’s first nomination and he became only the second black person to win an Oscar in the writing category, after Geoffrey Fletcher for “Precious.”

Ridley and producer-director Steve McQueen did not acknowledge each other during the acceptance speeches, indicating a possible rift between the two. But Ridley later told the New York Post that he had no intention of snubbing McQueen and said “I owe a lot to the genius of Steve McQueen, and I am forever grateful to have had the chance to work with him.”

Backstage, Ridley gave tribute to his parents — “who simply would not let me settle for second best” — and said he gets much of his writing done while parked in his car at his children’s school.

The “12 Years” script, based on the autobiography by Solomon Northup, is Ridley’s seventh dating back to 1997’s “U-Turn.” He also wrote “Three Kings,” “Undercover Brother,” “Red Tails” and “All Is By My Side” and TV series such as “Barbershop” and “Platinum.”

Ridley’s script for “12 Years a Slave” also won at the Spirit Awards on Saturday. But the script was ruled ineligible for WGA awards consideration because Ridley resigned from the guild during the bitter 2007-08 strike — a reminder of the many rifts that remain from the 100-day work stoppage. Many WGA activists remain scornful of Ridley six years later.

It’s not the first time that a script excluded by the WGA has gone on to win the Oscar with Quentin Tarantino’s “Django Unchained” and David Seidler’s “The King’s Speech” being notable recent examples. Both were ineligible because they were not under WGA jurisdiction.

Ridley delivered an emotional acceptance speech Saturday at the Spirit Awards, near tears as he said he had not fully realized the impact of the film until he saw it at the Toronto Film Festival.