Gilliam started work on the film in 1989 but was unable to secure funding until 1998 when it entered full pre-production with a budget of $32.1 million without American financing, with Jean Rochefort as Quixote, Johnny Depp as Toby Grummett – a 21st-century marketing executive thrown back through time – and Vanessa Paradis as the female lead.

Gilliam’s repeated attempts to relaunch production between 2003 and 2016 included Depp, Ewan McGregor and Jack O'Connell as Toby and Robert Duvall, Michael Palin and John Hurt as Quixote.

After yet another failed attempt, it was unexpectedly reported in March 2017 that filming had finally started, with Adam Driver, who was confirmed as Toby in 2016 and helped secure funding, and Jonathan Pryce, who had been part of the original 2000 production in a different role, as Quixote.

The final version of the film is set in modern-day rural Spain and now features Toby as a director shooting commercials and "Quixote" as an insane shoemaker convinced that he is the character from Cervantes' novel.

Gilliam faced difficulties in the process of releasing the film worldwide, partially due to a lengthy legal dispute with former producer Paulo Branco.

A follow-up to Lost in La Mancha, titled He Dreams of Giants and following the making of the final version of The Man Who Killed Don Quixote, was released in 2019.

After an unsuccessful day of shooting, Toby's superior, the Boss, introduces him to a Romani street merchant who sells him an old DVD of The Man Who Killed Don Quixote, a film he wrote and directed ten years earlier as a student.

Javier initially falters in his characterization, but upon rushing to defend teenage waitress Angelica when a member of Toby's crew plays a prank on her, succeeds in embodying that "I am Don Quixote".

Receiving a head wound after being knocked by one of the windmill's blades, Quixote and Toby are led by the woman to a decrepit ruin occupied by impoverished people.

That night, Toby comes to suspect that they are secretly terrorists, but soon finds that the ruin has transformed into a 17th-century village and its inhabitants are Moriscos hiding their Muslim faith from the Spanish Inquisition.

Toby manages to evade the inquisitors, then awakens the next morning, the night's events having seemingly been a dream, and learns that the residents are not terrorists but fearful undocumented immigrants.

Healing his wounds by a river, Toby is found by Jacqui on horseback, dressed for a costume party thrown by Alexei Miiskin, a Russian vodka company owner entering a business deal with the Boss.

Taking leave of his senses, he sets out to fix the world and revive chivalry, clad in makeshift armor and accompanied by a donkey-owning farmer named Sancho Panza, who serves as his squire".

[6][7] Phoenix Pictures chose Fred Schepisi to replace Gilliam, with John Cleese as Quixote and Robin Williams as Panza, and Steven Haft, Quincy Jones and David Salzman as producers.

"[6][7] After Schepisi's project collapsed, Gilliam resumed working on the film with co-writer Tony Grisoni, giving it the new name The Man Who Killed Don Quixote.

[23] The film quickly gained the reputation of being cursed, notably after the release of Lost in La Mancha, making it even harder for Gilliam to find financial support.

Those other productions mostly collapsed, like the Nicolas Cage-led The Defective Detective or an adaptation of Terry Pratchett and Neil Gaiman's novel Good Omens (which was cancelled after the September 11 attacks due to the content being judged too dark), or were also met with significant issues: he notably clashed with producers Bob and Harvey Weinstein on the making of The Brothers Grimm, leading to them firing his cinematographer Nicola Pecorini, and had to replace The Imaginarium of Doctor Parnassus's lead actor Heath Ledger after his death halfway through filming.

[37] In 2010, Gilliam stated that primary casting was finalised, with Duvall and McGregor still attached; however on 5 September of the same year, he revealed that funding had collapsed a month and half earlier and as a result shooting was delayed.

[15][38] By 2012, Duvall was still potentially attached to the film, but not McGregor, with Tony Grisoni commenting the same year "Us survivors of Don Q are a strange kind of dysfunctional family.

[43] In August 2014, in an interview with TheWrap, Gilliam revealed that he had received funding, and that the plot of the film has changed: "Our main character actually made a Don Quixote movie a lot earlier in his history, and the effect it had on many people wasn't very nice.

[2][58] Pryce had previously starred in Gilliam's films Brazil (1985), The Adventures of Baron Munchausen (1988), and The Brothers Grimm (2005), and was also cast in the original 2000 production of The Man Who Killed Don Quixote in a different role.

"[57] Cast members later announced included Joana Ribeiro, Óscar Jaenada, Jason Watkins, Rossy de Palma, and Jordi Mollà.

The accusation came from a report by Portuguese news channel RTP1, who stated that the crew had "left behind chipped masonry, broken roof tiles and uprooted trees at the 12th-century Convent of Christ in Tomar, central Portugal."

"[67] An investigation by the Portuguese government took place during the following weeks to determine if the news report was accurate, with the presence of "some damage" being acknowledged, which was catalogued by the convent officials who monitored the filming.

"[81] They added, "Our entire profession knows that 'forcing matters' has always been Mr. Branco's favorite method, and we should recall that he organized a press conference a few years ago where he denounced the Festival de Cannes because it had not kept a 'promise to select' one of his films.

According to the producer, they chose to remain quiet about the actual major details because it didn't feel necessary, but when Branco went public with his victory and claimed rights to the film, they felt they had to step forward and air all the "dirty laundry".

The website's critical consensus reads, "The Man Who Killed Don Quixote may not live up to long-gestating expectations, but it bears enough of director Terry Gilliam's signature creative stamp to satisfy fans.

[103] Peter Debruge with Variety called the film "a loud, belligerent, barely coherent mess", stating "the result feels like evidence of someone [Gilliam] who spent too long obsessing over Don Quixote, losing sight somewhere along the way of whatever attracted him in the first place.

[7][14][15][17][18][19][57][110][111][112] IndieWire called the film "one of the most troubled productions in the history of cinema", while /Film believed they "could write a book about the movie's problems", stating, "Heaven and hell seemed to unite in defiance of Terry Gilliam's The Man Who Killed Don Quixote".

The behind-the-scenes saga is part of the film's mystique and history, and whether it's great, terrible, or somewhere in between, that story is what historians, critics, and crowds will remember, long after the movie leaves theaters.