The actor - who is perhaps best known for his role of Ethan Rom in Lost - will appear in the drama's upcoming sixth season.
Mapother will play a leader of a team of mercenaries hired to kill money launderer Barry Burkowski (Paul Tei). His character is described as "cold-blooded and emotionally detached", says The Hollywood Reporter.
His appearance in the sixth episode of the season is scheduled to air in mid-July.
Scrubs star John C McGinley recently signed up to appear in an episode of Burn Notice as an old CIA mentor of Michael Westen (Jeffrey Donovan).
The sixth season is due to premiere on Thursday, June 14 at 9pm on the USA Network.
Watch a trailer for the sixth season of Burn Notice below: