[2] After starting his career on the television series My So-Called Life (1994), Leto made his film debut in How to Make an American Quilt (1995) and gained critical attention for his performance in Prefontaine (1997).

[3] Its second album, A Beautiful Lie (2005), pushed the band into the public eye, and the next releases, This Is War (2009) and Love, Lust, Faith and Dreams (2013), received further critical and commercial success.

His parents divorced when he was a child, and he and his older brother, Shannon, lived with their mother and their maternal grandparents, Ruby (Russell) and William Lee Metrejon.

[8] Leto said he "was raised around a lot of artists, musicians, photographers, painters and people that were in theater," adding that "Just having the art communal hippie experience as a child, there wasn't a clear line that was drawn.

[17] He found minor roles on television shows but his first break came in 1994 when he was cast opposite Claire Danes as Jordan Catalano, her love interest, in the short-lived but well-reviewed ABC teen drama My So-Called Life.

[24][25] That year, Terrence Malick cast Leto for a supporting role in the war film The Thin Red Line alongside Sean Penn and Adrien Brody.

[32] In 1999, Leto played a gay high school teacher who attracts the attention of Robert Downey, Jr.'s character in Black and White, and had a supporting role in the drama Girl, Interrupted, an adaptation of the memoir of the same name by Susanna Kaysen.

[15] The same year, he starred as heroin addict Harry Goldfarb in Requiem for a Dream, an adaptation of Hubert Selby, Jr.'s novel of the same name, directed by Darren Aronofsky and co-starring Ellen Burstyn, Jennifer Connelly, and Marlon Wayans.

Set in 1994, Jack Hayes (Leto) is caught with the wife of his employer, a Vegas thug, and flees to Seattle with his best friend, Pilot Kelvin (Jake Gyllenhaal), in the week preceding Kurt Cobain's suicide.

[37] During this period Leto focused increasingly on his music career, working with producers Bob Ezrin and Brian Virtue on his band's debut album 30 Seconds to Mars, which was released on August 27, 2002, in the United States through Immortal and Virgin.

[38] Upon its release, 30 Seconds to Mars was met with mostly positive reviews; music critic Megan O'Toole felt that the band managed to "carve out a unique niche for themselves in the rock realm.

The film failed in the United States; Stone attributed its poor reception to disapproval of the depiction of Alexander's bisexuality, but it succeeded internationally, with worldwide revenue of US$167 million.

The film received mixed reviews from critics; however, Leto's acting was widely praised; Heather Huntington from Reelz wrote that his "layered performance as the nattily dressing dandy with no remorse is truly impressive.

Determined to offset the impact that filming would have on the environment, Leto worked with the Natural Resources Defense Council to develop strategies that would minimize fuel consumption on the shoot.

[61] Upon release, "A Beautiful Lie" was met with widespread critical acclaim, resulting in various accolades, including the MTV Europe Music Award for Best Video.

His role required him to play various versions of his character, from 34 to 118 years old, spending six hours daily for the full make-up and adopting the voice of an old-aged man.

"[73] In 2009, Leto recruited scores of extras and all manner of surrealist street performers for the short film of "Kings and Queens", which features a critical mass movement founded with forward-thinking and eco-conscious intentions, through Los Angeles at night.

Critics lauded the simplicity of the video; James Montgomery from MTV wrote, "there's no denying the power of seeing tens of thousands of fans finding a simultaneous salvation, of a crowd of individuals becoming one.

"[88] The short film features several artists, including burlesque dancer Dita Von Teese, gymnasts McKayla Maroney and Jordyn Wieber, writer Neil Strauss and a number of animals.

[91] It was filmed during the Love, Lust, Faith and Dreams Tour and features live footage of Thirty Seconds to Mars onstage as well as fan commentary.

[92] Multiple monoliths and murals, including Michael Jackson and Marilyn Monroe impersonators, also appear, as well as homeless people hired by Leto himself for the video.

[93] After a five years hiatus from filming, Leto returned to act in the drama Dallas Buyers Club (2013), directed by Jean-Marc Vallée and co-starring Matthew McConaughey.

[99] In December of that year, Warner Bros. confirmed that Leto would play the role of the Joker in Suicide Squad (2016), a supervillain film based on the comic book series of the same name.

Fellow Suicide Squad cast member Will Smith, who played Deadshot in the film, stated that he had "never actually met Jared Leto", saying, "We worked together for six months and we've never exchanged a word outside of 'action!'

"[101] Leto's method acting on Suicide Squad also reportedly involved sending unorthodox gifts to his fellow cast members,[101] including live rats and bullets.

[115] Leto later also appeared in 2036: Nexus Dawn, a promotional short film that takes place before Blade Runner 2049 directed by Luke Scott and co-starring Benedict Wong.

[122] He plays Adam Neumann alongside Anne Hathaway in Apple+'s 2022 WeCrashed about the rise and fall of the WeWork, for which he was nominated for a Best Actor in a Miniseries, Limited Series, or Motion Picture Made for Television.

[135] After the strong relationship between Thirty Seconds to Mars and its audience, Leto launched the social media management and digital marketing company The Hive.

[149] In June 2008, he joined Habitat for Humanity to work with Thirty Seconds to Mars on a home being repaired and renovated through the Greater Los Angeles Area's "A Brush With Kindness" programme.

[153] In February 2015, Leto was named a global ambassador for World Wide Fund for Nature (WWF), supporting online fundraisers and leading one for his 47th birthday in 2018.