Martin became the leader of the team following the Ron Artest trade during the offseason. He started the season strong, however he suffered an ankle injury which kept him out 15 games. He returned, but re-aggravated his injury shortly thereafter. After returning again, he helped the Kings snap a 6-game losing streak. Martin averaged 24.6 points per game during the remainder of the season, including an overtime loss on April 1, 2009, against the Golden State Warriors, in which he scored a career-high 50 points and became the first King to score 50-plus since Chris Webber in 2001. On November 2, 2009, Martin scored 48 points including 7–10 from three-point range to lead the Kings to an overtime victory over the Memphis Grizzlies.
