His character in the show Burn Notice named Michael Westen. Michael Westen is a spy who got burned ( fired ) and is trying to figure out who did it and why.
The show is very well written, and its pretty much down to the actors to make the show "big". Jeffrey plays the lead role and the show wouldnt be the same without him, Michael would be a hard person to act, due to his amazing character in the show.
Michael adds plenty of humour and action in the Burn Notice series, and has a very unique attitude and style in the show.