The Hot Fuzz actor will voice the bounty hunter Dengar - who first featured in The Empire Strikes Back.
Dengar was one of the bounty hunters recruited by Darth Vader in the 1980 film to find the Millennium Falcon.
"Dengar is one of the elite," Pegg told Entertainment Weekly. "If you're on Darth Vader's bounty-hunter speed dial, you are the best in the galaxy.
"It was a total honour to play this mysterious, hard man from my favourite Star Wars movie, The Empire Strikes Back."
Dengar went on to become a cult figure in the Star Wars universe, and his backstory has been further explored in various Star Wars canon.
Pegg's role of Dengar will air on Friday, March 2 on the Cartoon Network.
Simon Pegg will return as Scotty for Star Trek 2, which began filming last month.
Watch the promo for Simon Pegg in the episode 'Bounty' below: