In a flash forward, following his collapse while working at the Omaha Cinnabon, a nervous “Gene” has a worrying encounter with a hospital clerk who needs his personal information for billing purposes. During his taxi ride to the mall to retrieve his car, Gene becomes suspicious of the driver, Jeff, whose cab displays an Albuquerque Isotopes air freshener.
He exits before reaching the mall and walks around the corner out of the driver’s sight. In 2003, Jimmy and Kim learn of Chuck’s death, and believing himself responsible, Jimmy falls into depression.
Howard arranges Chuck’s funeral, and later admits that he believes his decision to dismiss Chuck from HHM caused Chuck’s suicide. Howard explains that Chuck’s malpractice insurance rates had become exorbitant – not realizing Jimmy was to blame for reporting Chuck’s instability to the insurers. Jimmy allows Howard to take the blame and quickly regains his happy-go-lucky demeanor.
Mike performs actual security and safety consulting for Madrigal Electromotive and details a list of violations he uncovered on his first site visit. Following Hector’s stroke, the cartel bosses direct Nacho and Arturo to take over Hector’s drug operation. Gus remains suspicious of Nacho and has Victor follow him.
- Mark Margolis as Hector Salamanca, the patriarch of a brutal family of drug enforcers in Don Eladio’s Mexican cartel, incapacitated via a stroke at the end of season three.
- Kerry Condon as Stacey Ehrmantraut, Mike’s widowed daughter-in-law and the mother of Kaylee Ehrmantraut
- Jeremiah Bitsui as Victor, Gus’ henchman.
- Vincent Fuentes as Arturo, a criminal associate of Nacho Varga and Hector Salamanca.
- Ann Cusack as Rebecca Bois, Chuck’s ex-wife.
- Dennis Boutsikaris as Rich Schweikart, the attorney for Sandpiper Crossing in the class action lawsuit Jimmy develops.
- Andrew Friedman as Mr. Neff, manager of Neff Copiers.
- Poorna Jagannathan as Dr. Maureen Bruckner, Johns Hopkins stroke-recovery specialist, funded by Gus Fring’s grant to oversee Hector’s treatment.
- Daniel Moncada and Luis Moncada as Leonel and Marco Salamanca, Hector’s nephews, Tuco’s cousins, brutal hitmen for the Eladio cartel.
- Javier Grajeda as Juan Bolsa, Eladio cartel under boss
- Ray Campbell as Tyrus Kitt, a henchman on Gus Fring’s payroll.
- Juan Carlos Cantu as Manuel Varga, Nacho’s father, owner of an upholstery shop.
- Abigail Zoe Lewis as Kaylee Ehrmantraut, Mike’s granddaughter.
- Rex Linn as Kevin Wachtell, the CEO of Mesa Verde Bank, now Kim’s only client.
- Cara Pifko as Paige Novick, the senior counsel of Mesa Verde Bank and Trust.
- Franc Ross as Ira, a burglar Jimmy conspires, and the owner of Vamonos Pest.
- Keiko Agena as Viola Goto, Kim’s paralegal.
- Tommy Nelson as Rocco, the leader of the thugs who mug Jimmy at House of Dogs.
- Carlin James as Zane, a thug who mugs Jimmy.
- Cory Chapman as Jed, a thug who mugs Jimmy.
- Eileen Fogarty as Mrs. Nguyen, owner of a nail salon and Jimmy’s landlord.
- David Costabile as Gale Boetticher, an idealistic college chemistry student on scholarship.
- Rainer Bock as Werner Ziegler, a German engineer hired by Gus to plan and oversee the construction of his underground meth “superlab”
- Stefan Kapičić as Casper, a member of Werner Ziegler’s team for the construction of Gus’s meth “superlab”
- Ben Bela Böhm as Kai, a member of Werner Ziegler’s construction team, who Mike holds in contempt
- Lavell Crawford as Huell Babineaux, a professional pickpocket hired by Jimmy for security.
- Michael McKean as Chuck McGill, who appears in flashbacks, Jimmy’s deceased elder brother and a founding partner of HHM. Chuck committed suicide at the end of the third season.
- Josh Fadem as Camera Guy, a UNM film student, helps Jimmy on various endeavors.
- Hayley Holmes as Drama Girl, UNM film student who helps Jimmy on various projects and schemes.
- Julian Bonfiglio as Sound Guy, UNM film student who helps Jimmy.
- Tony Dalton as Lalo Salamanca, acting head of the brutal Salamanca family of cartel enforcers, fixer for Don Eladio’s Albuquerque distribution.
- Ethan Phillips as Benedict Munsinger, a judge.
- Ed Begley Jr. as Clifford Main, founding partner of Davis & Main, Jimmy’s former employer in the second season.
- Don Harvey as Jeff, a cab driver that Gene encounters.
- Laura Fraser as Lydia Rodarte-Quayle, a Madrigal Electromotive executive and associate of Gus Fring.
- JB Blanc as Barry Goodman, Gus Fring’s medical counsel.
- Joe DeRosa as Dr. Caldera, a veterinarian who serves as Mike and Jimmy’s liaison to the criminal underworld.
- Tamara Tunie as Anita, a member of Mike’s widower’s support group.
- Tina Parker as Francesca Liddy, Jimmy’s receptionist.
- Peter Diseth as Bill Oakley, a deputy district attorney.
- Max Arciniega as Krazy-8 Molina, a meth distributor working for Nacho and the Salamanca family.
- Brandon K. Hampton as Ernesto, Chuck’s paralegal/assistant, appears in a flashback.