Here’s a guide to the main cast and characters of spinoff NCIS: Los Angeles. NCIS came from humble beginnings, starting as a backdoor pilot during JAG season 8. Agent Gibbs (Mark Harmon) and DiNozzo first appeared in a two-parter episode, which was popular enough for CBS to greenlight a solo series. While the first few seasons of NCIS had respectable ratings, it grew over time to become one of the most-watched shows in America. It’s now run for seventeen seasons and over 300 episodes to date.

Naturally, those are the kind of numbers that make a network feel confident, so a spinoff arrived in the form of NCIS: Los Angeles in 2009. Like the title suggests, this show deals with the L.A. branch, and the show has lasted for eleven seasons thus far. The franchise received a second spinoff with NCIS: New Orleans in 2014, starring Scott Bakula and CCH Pounder. In keeping with the robust success of the brand, New Orleans is returning for a sixth season in late 2019.

The key to the success of every incarnation of NCIS is the cast and the chemistry between the characters. NCIS: Los Angeles is no different, so here’s a quick guide to the key players on the show.

Chris O’Donnell - Grisha Callen

Callen is played by Chris O’Donnell (Batman & Robin) and is a highly skilled agent assigned to the NCIS’ Los Angeles branch. Callen’s past was a mystery during early seasons, and while he was something of a lone wolf, his fellow agents gradually became family to him. He speaks several languages and is highly regarded among his peers.

LL Cool J - Sam Hanna

LL Cool J plays Sam Hanna, Callen’s partner and another top agent in the L.A. branch. He’s an ex-Navy SEAL, a devout Muslim and has a wife and children. He’s more of a team player than Callan and has a fear of clowns.

Linda Hunt - Henrietta Lange

Henrietta is the Operational Manager in NCIS: Los Angeles. She’s a veteran agent - having served during the Cold War - and is responsible for turning Callen into an agent. In spite of her size, “Hetty” inspires plenty of fear and respect from her agents due to her distinguished career.

Eric Christian Olsen - Marty Deeks

Marty Deeks (Eric Christian Olsen, The Thing 2011) was recurring character during NCIS: Los Angeles season 1 who later became a part of the main cast. Marty is the LAPD liaison officer to the NCIS, and in addition to being a lawyer, he’s married to fellow agent Kensi.

Daniela Ruah - Kensi Blye

Kensi is the daughter of a Marine and spent part of her childhood on the streets. She’s skilled at undercover missions and is married to her partner Marty.

Renée Felice Smith - Nell Jones

Nell is NCIS: Los Angeles’ intelligence analyst who works closely with Hetty. She has a high IQ, is skilled in firearms and is involved with Agent Eric Beale.

Barrett Foa - Eric Beale

Barrett Foa (Will & Grace) plays Eric Beale on NCIS: Los Angeles, the team’s resident techie. He’s not as skilled in weaponry or fieldwork but is still an invaluable asset to the gang.

Next: A Guide To Patrick St. Esprit’s Many NCIS Universe Characters