The Clippers announced the deal Friday with the nine-year NBA veteran who spent the past two seasons down the hall at Staples Center with the Lakers.
Barnes begins his second stint with the Clippers after playing 38 games for the club during the 2003-04 season. The well-traveled UCLA product has played for eight NBA teams, including all four California franchises.
Barnes was the top-scoring reserve on the NBA's lowest-scoring bench last season, averaging 7.8 points and 5.5 rebounds per game for the Lakers.
Barnes joins fellow Clippers newcomers Lamar Odom, Grant Hill, Jamal Crawford and Ronny Turiaf in a roster overhaul for a club coming off a second-round playoff appearance and just its second winning season in two decades.