Mark Alan Ruffalo (; born November 22, 1967) is an American actor and producer. He began acting in the early 1990s and first gained recognition for his work in Kenneth Lonergan's play This Is Our Youth (1998) and drama film You Can Count On Me (2000). He went on to star in the romantic comedies 13 Going on 30 (2004) and Just like Heaven (2005) and the thrillers Zodiac (2007) and Shutter Island (2010); and received a Tony Award nomination for his supporting role in the Broadway revival of Awake and Sing! in 2006. He has also starred in Dark Waters (2019). He gained international recognition for playing Bruce Banner / Hulk in the Marvel Cinematic Universe superhero films The Avengers (2012), Avengers: Age of Ultron (2015), Thor: Ragnarok (2017), Avengers: Infinity War (2018), and Avengers: Endgame (2019).
Ruffalo gained nominations for the Academy Award for Best Supporting Actor for playing a sperm donor in the comedy-drama The Kids Are All Right (2010), Dave Schultz in the biopic Foxcatcher (2014), and Michael Rezendes in the drama Spotlight (2015). He won the Screen Actors Guild Award for Best Actor in a TV Movie for playing a gay writer and activist in the television drama film The Normal Heart (2015).
He is also known as Mark Alan Ruffalo.