Jared Joseph Leto (; born December 26, 1971) is an American actor and musician. Known for his method acting in a variety of roles, he has received numerous accolades over a career spanning three decades, including an Academy Award and a Golden Globe Award. Additionally, he is recognised for his musicianship and eccentric stage persona as a member of the rock band Thirty Seconds to Mars.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). After supporting roles in The Thin Red Line (1998), Fight Club (1999), Girl, Interrupted (1999) and American Psycho (2000), he received widespread praise for his lead role in Requiem for a Dream (2000). He then began focusing increasingly on music, returning to acting with Panic Room (2002), Alexander (2004), Lord of War (2005), Chapter 27 (2007), and Mr. Nobody (2009). His performance in Dallas Buyers Club (2013) earned him the Academy Award for Best Supporting Actor. He has since starred in Suicide Squad (2016), Blade Runner 2049 (2017), The Little Things (2021), House of Gucci (2021), and Morbius (2022).

Leto is the lead vocalist, multi-instrumentalist and main songwriter for Thirty Seconds to Mars, a band he formed in 1998 with his older brother Shannon Leto. Its debut album, 30 Seconds to Mars (2002), was released to positive reviews but to limited commercial success. 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. It was followed by America (2018), which polarized critics upon release. The band has sold over 15 million albums worldwide.