Joaquin Rafael Phoenix (; né Bottom; born October 28, 1974) is an American actor. Known for playing dark and unconventional characters in independent films, he has received various accolades, including an Academy Award, a British Academy Film Award, a Grammy Award, and two Golden Globe Awards. In 2020, The New York Times named him one of the greatest actors of the 21st century.Phoenix began his career by appearing in television series in the early 1980s with his brother River. His first major film roles were in SpaceCamp (1986) and Parenthood (1989). During this period, he was credited as Leaf Phoenix, a name he gave himself. He took back his birth first name in the early 1990s and received critical acclaim for his supporting roles in the comedy-drama To Die For (1995) and the period film Quills (2000). Phoenix received further critical acclaim and a nomination for the Academy Award for Best Supporting Actor for his portrayal of Commodus in the historical drama Gladiator (2000). He had success with the horror films Signs (2002) and The Village (2004), the historical drama Hotel Rwanda (2004), and won a Grammy Award, a Golden Globe Award and a nomination for the Academy Award for Best Actor for his portrayal of musician Johnny Cash in the biopic Walk the Line (2005).

Following a brief sabbatical, Phoenix starred in the psychological drama The Master (2012), winning the Volpi Cup for Best Actor and earning his third Academy Award nomination. He received Golden Globe Award nominations for his roles in the romantic drama Her (2013) and the crime satire Inherent Vice (2014), and won the Cannes Film Festival Award for Best Actor for the psychological thriller You Were Never Really Here (2017). Phoenix won the Academy Award for Best Actor for playing the title character in Joker (2019).

Phoenix is an animal rights activist. He has been vegan since the age of three and regularly supports charitable causes and has produced several documentaries on global meat consumption and its impact on the environment. He is in a relationship with actress Rooney Mara, with whom he has a son.