He was cast as a series regular in the CBS police procedural NCIS: Los Angeles, a spin-off of the NCIS. LL Cool J plays Special Agent Sam Hanna, an ex – Navy SEAL who is fluent in Arabic and an expert on West Asian culture. The series debuted in autumn of 2009, but the characters were introduced in an April 2009 crossover episode on the parent show.
He does a good job.
I think he does well on the show, too. In fact, I think the Los Angeles version of NCIS has eclipsed the original, which IMO has jumped the shark this year.