Mason flew to Sacramento to meet with Kings officials and take a physical on Wednesday. The Kings announced the deal after getting the results of the physical Thursday. His deal is not guaranteed and will pay him the league minimum of $1.18 million.
Mason, who turns 32 in October, played only 39 games last season for Oklahoma City, missing the second half of the season with a hyperextended right knee. He started 18 games, averaging 7.5 points and 4.0 rebounds for the season.
Mason was one of the Thunder's most popular players after playing in college at Oklahoma State and later returning to Oklahoma City when the New Orleans Hornets spent most of two seasons in the city after Hurricane Katrina. He joined the Thunder last season.
Mason burst onto the scene as a rookie by winning the 2001 slam dunk contest while with the Seattle SuperSonics. He's also had two stints with the Milwaukee Bucks. For his nine-year career, Mason has averaged 12.2 points and 4.5 rebounds.