Walter Hartwell White Sr., also known by his alias Heisenberg, is the fictional antihero[a] turned villain protagonist of the American crime drama television series Breaking Bad, portrayed by Bryan Cranston.

After this discovery, White decides to manufacture and sell methamphetamine with a former student, Jesse Pinkman (Aaron Paul), to ensure his family's financial security after his death.

Cranston reprised the role of Walt in a flashback for Breaking Bad's sequel film El Camino, and again in the sixth and final season of the prequel series Better Call Saul, making him one of the few characters to appear in all three, alongside Jesse Pinkman, Mike Ehrmantraut (Jonathan Banks), Ed Galbraith (Robert Forster), and Austin Ramey (Todd Terry).

As the premise of Breaking Bad was based on a humorous idea that he and his fellow writer from The X-Files, Thomas Schnauz had come up with of driving around in an RV making methamphetamine, Gilligan made White a chemistry teacher, one who, until the start of the show, would have never violated the law.

"[6][10] AMC officials were initially reluctant with the casting choice, having known Cranston only as the over-the-top character Hal on the comedy series Malcolm in the Middle and approached actors John Cusack and Matthew Broderick about the role.

He collaborated with costume designer Kathleen Detoro on a wardrobe of mostly neutral green and brown colors to make the character bland and unremarkable, and worked with makeup artist Frieda Valenzuela to create a mustache he described as "impotent" and like a "dead caterpillar".

However, after a disastrous 4th of July Party, where they had intended to announce their engagement, Walter instead left both Gretchen and Gray Matter Technologies, selling his financial interest in the company for $5,000.

[27] Walt's other family includes Skyler's sister, Marie Schrader (Betsy Brandt); her husband, Hank (Dean Norris), who is a DEA agent; and his mother, who is never seen.

The pair begin to fear for their lives when, after testing the purity of the meth they delivered by snorting some of it, Tuco senselessly beats to death one of his own men, No-Doze (Cesar Garcia).

Walt takes off all his clothes in a grocery store in order to explain his disappearance by claiming that he had gone into a fugue state as a result of his cancer medication and simply wandered off.

Seeing that Walt and Jesse need a new distributor to sell the large quantity of product they have remaining, Saul arranges a meeting at a local restaurant with a mysterious meth kingpin.

Walt breaks into Jesse's apartment where the meth is stored and finds him passed out with his girlfriend and fellow heroin addict Jane Margolis (Krysten Ritter).

After talking to a stranger at a bar about family – not knowing that the man is Jane's father Donald (John de Lancie) – Walt again breaks into Jesse's apartment to find the lovers passed out in a heroin stupor.

To avoid being discovered hiding in the RV, Walt and Jesse, aided by Saul, place a phone call to distract Hank, making him believe his wife Marie (Betsy Brandt) has been injured in a car accident.

Walt tries to use one of Saul's connections to get him and his family relocated but finds that Skyler has used most of his drug money to pay off Ted Beneke's IRS fines to avoid having their own lives investigated.

When Andrea's young son Brock (Ian Posada) falls desperately ill with ricin-like symptoms, Jesse attacks Walt, believing that he poisoned the boy.

When Walt arrives in Albuquerque – on his 52nd birthday – he confronts Gretchen and Elliott at their home and coerces them into putting his remaining money into a trust fund for Walter Jr.

He then visits Skyler and provides her with the location of Hank and Steve's unmarked grave, which he suggests she use to barter for a deal with the prosecutor, and finally admits to her that he entered the meth business for himself, not his family.

Now out of range, he activates a remote machine gun mounted in his car that injures Jack and kills all of his men except for Todd, whom Jesse strangles to death with a chain.

Walt is briefly mentioned in passing by Saul Goodman (now going by the alias Gene Takavic) as he attempts to explain to Jeff how crazy his life had become and how much money he could earn by getting into "the game".

As Walt had hoped, Skyler had succeeded in getting a deal with the federal prosecutors and the DEA was ultimately forced to release Huell Babineaux, leaving only Jesse and Saul left for them to go after.

Although Jesse has successfully managed to escape to Alaska while tricking the public into thinking he fled to Mexico, the DEA has seized all of Saul's assets and is even following Francesca in an attempt to find him.

"[34] In their list for the "Top 100 Villains", IGN ranked Walt as #12, stating that "Walter White is selfishness incarnate, and perhaps one of the greatest tragic figures to ever grace television, making his ultimate descent into villainy that much more compelling.

[36]Similarly, Scott Meslow wrote in The Atlantic that Walt's capacity for villainy was present well before the series even began, and that cancer was only the catalyst, stating that "all the elements that have since turned him into a monster were already in place.

"[37] New York magazine writer Emma Rosenblum said Bryan Cranston "pulls off the unassuming White with flawless subtlety: a waxy pallor, a slump of the shoulders, and a sense of doom that is palpable".

[43][44] At the annual Golden Globe Awards, Cranston has been nominated for the Best Actor – Television Series Drama accolade on four occasions for his role in Breaking Bad, in 2011, 2012, 2013 and 2014, winning in 2014 for the second half of season five.

[48][49] Cranston reprised his role of the character in a commercial for Esurance which aired during Super Bowl XLIX, one week before the premiere of Breaking Bad spin-off Better Call Saul.

[56] On October 19, 2013, actor Jackamoe Buzzell organized a mock funeral procession (including a hearse and a replica of Walt's meth lab RV) and service for the character was held at Albuquerque's Sunset Memorial Park cemetery.

[57][58] Many fans of Breaking Bad, including actor Norm Macdonald and New Yorker magazine writer Emily Nussbaum,[59] proposed a theory, in which most of the series finale happened in Walt's mind, and he really died in the stolen Volvo in the beginning of it.

[62] However, series creator Vince Gilligan debunked this theory, explaining that Walt could not possibly have known several things that happened, like Jesse being held in captivity by Jack's gang instead of being murdered by them, or that Todd had begun taking meetings with Lydia regarding the meth trade.