Season 4 returned stars Jason Earles, Leo Howard, Mateo Arias and Dylan Riley Snyder while Olivia Holt guest starred mid-season since she was starring in a new production on Disney Channel, I Didn’t Do It.
- Leo Howard as Jack Brewer (18/18)
- Dylan Riley Snyder as Milton Krupnick (18/18)
- Mateo Arias as Jerry Martínez (18/18)
- Jason Earles as Rudy Gillespie (18/18)
- Olivia Holt as Kim Crawford (3/18) (Special Guest Star)
- Brooke Dillman as Joan Malone
- Dan Ahdoot as Falafel Phil
- Veronica Dunne as Taylor
- Ian Reed Kesler as Sensei Ty
- Scott Dunn as Shane Peters
- Valorie Hubbard as Mama Sparkle
- Eric Tiede as Izzy Gunnar
- Hannah Leigh as Julie
- Joel McCrary as Bobby Wasabi
- Eric Nenninger as Funderburk
- Harrison Thomas Boxley as Sidney
- 02/17/14 - The Boys are Back in Town (401)
- 02/24/14 - Gold Diggers (403)
- 03/03/14 - From Zeros to Heroes (404)
- 03/10/14 - The Stang (406)
- 03/31/14 - Nerd With a Cape (405)
- 04/07/14 - RV There Yet? (402)
- 04/14/14 - Invasion of the Ghost Pirates (410)
- 06/16/14 - The Amazing Krupnick (408)
- 06/23/14 - The Battle of Seaford Hill (412)
- 06/30/14 - Fight at the Museum (411)
- 07/18/14 - Tightroping the Shark (414)
- 07/21/14 - Full Metal Jack (413)
- 07/28/14 - Martinez & Malone: Mall Cops! (415)
- 08/04/14 - Seaford Hustle (409)
- 11/17/14 - Kickin’ It In The Office (407)
- 03/04/15 - Bringing Down The House (416)
- 03/11/15 - You Don't Know Jack (417)
- 03/25/15 The Grandmaster (418)
- Former member of the main cast, Olivia Holt, is not going to return as Kim in the fourth season (confirmed by Olivia Holt). This makes the second season to lose a main cast member, the first was Alex Christian Jones, who left after the Season 2 finale. However, she appears in three episodes.
- In this season Rudy opens up a new dojo and Phil opens up a Bowling Alley which Jerry now works at.
- Kim returned as a guest star for the episode Seaford Hustle, You Don't Know Jack, and The Grandmaster
- It is unknown if Jack and Milton may still have future spy missions since Funderburk said their spy days are over.
- jack directed Fight at the Museum.
- This is the final season of the show.
- The series finale aired on March 25th, 2015.