John Paul Cusack (; born June 28, 1966) is an American actor, producer, screenwriter and political activist. He is a son of filmmaker Dick Cusack and the younger brother of actresses Joan and Ann Cusack.

Cusack began acting in films during the 1980s, starring in coming-of-age dramedies such as The Sure Thing (1985), Better Off Dead (1985), and Say Anything... (1989). He then started appearing in independent films such as Eight Men Out (1988), The Grifters (1990), True Colors (1991), and Bullets Over Broadway (1994). Cusack began appearing as a leading man in such film as the comedic films Grosse Pointe Blank (1997), the action thriller Con Air (1997), the animated musical Anastasia (1997), the psychological drama Being John Malkovich (1999), and the romantic comedies High Fidelity (2000), America's Sweethearts (2001), Serendipity (2001), and Must Love Dogs (2005). He also starred in Runaway Jury (2003), Grace Is Gone (2007), Martian Child (2007), Hot Tub Time Machine (2010), The Butler (2013), Maps to the Stars (2014), and Chi-Raq (2015). He portrayed Brian Wilson in the critically acclaimed musical biopic Love and Mercy (2015).