Phillips promoted Joker by posting on set photos on his Instagram account.[130] On September 21, 2018, he released test footage of Phoenix in-costume as the Joker, with "Laughing" by The Guess Who accompanying the footage.[131] At CinemaCon on April 2, 2019, Phillips unveiled the first trailer for the film,[31] which was released online the following day.[132] The trailer, prominently featuring the song "Smile" performed by Jimmy Durante, generated positive responses, with some commentators comparing it to Taxi Driver and Requiem for a Dream (2000) and praising Phoenix's performance.[133][134] Writers described the trailer as dark and gritty,[135] with ComicBook.com's Jenna Anderson feeling it appeared more like a psychological thriller than a comic book film.[31] Actor Mark Hamill, who has voiced the Joker since the cartoon Batman: The Animated Series (1992-1995), expressed enthusiasm on Twitter.[136] Conversely, io9's Germain Lussier said the trailer revealed too little and that it was too similar to photos Phillips had posted on Instagram. While he still believed it exhibited potential, Lussier overall thought the trailer was not "a home run".[137] The trailer received over eight million views in the first few hours of release.[138]
On August 25, 2019, Phillips released six brief teasers that contained flashes of writing, revealing the second trailer would be released on August 28.[139] Filmmaker Kevin Smith commended the trailer, stating he thought the film "would still work even if [DC Comics] didn't exist" and praising its uniqueness.[140] Overall, Deadline Hollywood estimated that Warner Bros. spent $120 million on promotion and advertisements.[3]
After release in theaters, Warner Bros. used negative critics on this film for promotion.[141]
