Born in Germany to a mother from Northern Ireland and a German father, Fassbender relocated to Ireland at age two.[a] He made his feature film debut in 300 (2006). Early roles include in the HBO miniseries Band of Brothers (2001) and the Sky One fantasy drama Hex (2004–2005). Fassbender first came to prominence playing Bobby Sands in Hunger (2008), for which he won a British Independent Film Award. Subsequent roles include the 2009 films Fish Tank and Inglourious Basterds, and the 2011 films Jane Eyre and A Dangerous Method. He gained mainstream success for playing Erik Lehnsherr / Magneto in X-Men: First Class (2011), X-Men: Days of Future Past (2014) and X-Men: Apocalypse (2016), and David 8 and Walter One in Prometheus (2012), and its sequel, Alien: Covenant (2017).

For his portrayal of a sex addict in Steve McQueen's drama Shame (2011), Fassbender won the Volpi Cup for Best Actor and was nominated for Golden Globe and BAFTA Award. His performance as Edwin Epps in 12 Years a Slave (2013) earned him a nomination for the Academy Award for Best Supporting Actor. He also starred in The Counselor (2013), Frank (2014), Macbeth, and Steve Jobs (both 2015). Fassbender received another Academy Award nomination for his portrayal of the title role in the latter. After a hiatus, he starred in the action thriller film The Killer (2023).

Fassbender began competing in auto racing in 2017 with the Ferrari Challenge. As of 2023, he races in the European Le Mans Series, driving for Proton Competition. He married Swedish actress Alicia Vikander in 2017.