NCIS Season 19 premiered on September 20, 2021.
|Leroy Jethro Gibbs||Mark Harmon||NCIS Special Agent in Charge.||Resigned.|
Episodes 1–4 only
|Timothy (Tim) McGee||Sean Murray||NCIS Senior Special Agent who is currently in charge of the NCIS Major Case Response Team.|
|Nicholas (Nick) Torres||Wilmer Valderrama||NCIS Special Agent.|
|Jessica Knight||Katrina Law||NCIS Special Agent.|
|James (Jimmy) Palmer||Brian Dietzen||Chief Medical Examiner.||Former Medical Assistant.|
|Kasie Hines||Diona Reasonover||NCIS Forensic Specialist.|
|Donald Mallard||David McCallum||NCIS Historian||Former Medical Examiner|
|Leon Vance||Rocky Carroll||Director of NCIS.|
|Alden Parker||Gary Cole||FBI Special Agent.||Episode 2–|
- On Tuesday, June 22, 2021, it was announced that Gary Cole (Alden Parker) had joined the series where Mark Harmon (Leroy Jethro Gibbs) is reducing more episodes and Katrina Law (Jessica Knight) had been promoted to series regular and that she was the replacement for Emily Wickersham (Eleanor Bishop).
- David McCallum (Ducky Mallard) is now credited before Rocky Carroll (Leon Vance), as well as receiving a "with" billing. Gary Cole (Alden Parker) now receives the "and" billing.
- After 19 years, Mark Harmon (Leroy Jethro Gibbs) departs the series after the fourth episode as a series regular.
- On April 15, 2021, the main series has renewed for 19th season.
- This season will be the first time to show on Mondays instead of Tuesdays and at 9:00 instead of 8:00.
- This is Mark Harmon (Leroy Jethro Gibbs) final season and has exited after nineteen seasons, respectively.
|415||1||1901||Blood in the Water (episode)||September 20, 2021||As the team searches for Gibbs after wreckage from his boat is discovered, they find out he was tracking a serial killer with journalist Marcie Warren, who wrote an exposé on him.|
|416||2||1902||Nearly Departed (episode)||September 27, 2021||While trying to find the serial killer Gibbs was after, the team discovers another person has been tracking the case as well.|
|417||3||1903||Road to Nowhere (episode)||October 4, 2021||Gibbs and Parker go on a road trip to find one of the serial killer's victims. Also Knight goes undercover at a large manufacturing company with ties to the murders.|
|418||4||1904||Great Wide Open (episode)||October 11, 2021||Gibbs and McGee head to Alaska while the team works at home to uncover the conspiracy behind the serial killer.|
|419||5||1905||Face the Strange (episode)||October 18, 2021||The team investigates the death of a Navy commander whose body suddenly explodes before Jimmy can examine it.|
|420||6||1906||False Start (episode)||November 1, 2021||The team investigates the death of a beloved Navy commander who trained some of the top athletes in the country.|
|421||7||1907||Docked (episode)||November 8, 2021|
|Seasons of NCIS|
|NCIS Season 1 ♦ NCIS Season 2 ♦ NCIS Season 3 ♦ NCIS Season 4 ♦ NCIS Season 5 ♦ NCIS Season 6 ♦ NCIS Season 7 ♦ NCIS Season 8 ♦ NCIS Season 9 ♦ NCIS Season 10 ♦ NCIS Season 11 ♦ NCIS Season 12 ♦ NCIS Season 13 ♦ NCIS Season 14 ♦ NCIS Season 15 ♦ NCIS Season 16 ♦ NCIS Season 17 ♦ NCIS Season 18 ♦ NCIS Season 19