Following the NHL Lockout, the Flyers surprised everyone by signing Peter Forsberg on August 3, 2005. In order to clear salary cap space for Forsberg's contract, Roenick was traded the next day to the Los Angeles Kings.

Roenick's 2005–06 season with the Kings was greatly disappointing, both for Roenick and for the team. He managed 22 points in 58 games, his lowest total since he scored 18 points in 20 games in his rookie season. It was a trying season for Roenick who missed time due to a broken finger suffered while blocking a shot during a penalty kill, played games late in the season after suffering a chip fracture in his right ankle[19] and, the concussion suffered from the slapshot had changed Roenick's game making him a tentative player. Roenick was displeased with his performances stating in an almost apologetic way "I went to LA to finish off the last year of my contract and had a year off playing [lockout] and it was a really difficult year for me, it was hard mentally. A lot of people don’t realize that for six months I had a lot of problems with the concussions and battling the jaw injury …".

Becoming a free agent at the end of his first season in Los Angeles, he expressed strong interest in joining a Canadian team. "It was a nightmare season from hell last year," Roenick said, "I've always said I would like to play in Canada before my career is over".

The highlight of Roenick's time in LA may very well have been dancing on the ice during a preseason game in Las Vegas.