Actor Ralph Fiennes first achieved success onstage at the Royal National Theatre as a noted Shakespeare interpreter. Fiennes first worked on screen in 1990 and then made his film debut in 1992 as Heathcliff in Emily Brontë's Wuthering Heights (1992), opposite Juliette Binoche. 1993 was his "breakout year". He had a major role in the controversial Peter Greenaway film The Baby of Mâcon (1993), with Julia Ormond, which was poorly received. Later that year he became known internationally for portraying the amoral Nazi concentration camp commandant Amon Goeth in Steven Spielberg's Schindler's List (1993). For this he was nominated for the Academy Award for Best Supporting Actor and the Golden Globe Award for Best Supporting Actor. He did not win, but did win the Best Supporting Actor BAFTA Award for the role, as well as Best Supporting Actor honors from numerous critics groups, including the National Society of Film Critics, and the New York, Chicago, Boston, and London Film Critics associations. His portrayal as Göth also earned him a spot on the American Film Institute's list of Top 50 Film Villains. To look suitable to represent Goeth, Fiennes gained weight, but he managed to shed it afterwards. In 1994, he portrayed American academic Charles Van Doren in Quiz Show (1994). In 1996, he was nominated for the Academy Award for Best Actor for his performance as Count Almásy the World War II epic romance, and another Best Picture winner, Anthony Minghella's The English Patient (1996), in which he starred with Kristin Scott Thomas. He also received BAFTA and Golden Globe nominations, as well as two Screen Actors Guild (SAG) Award nominations, one for Best Actor and another shared with the film's ensemble cast.

Since then, Fiennes has been in a number of notable films, including Strange Days (1995), Oscar and Lucinda (1997), the animated The Prince of Egypt (1998), István Szabó's Sunshine (1999), Neil Jordan-directed films The End of the Affair (1999) and The Good Thief (2002), Red Dragon (2002), Maid in Manhattan (2002), The Constant Gardener (2005), In Bruges (2008), The Reader (2008), co-starring Kate Winslet, Kathryn Bigelow's Oscar®-winning The Hurt Locker (2008), Clash of the Titans (2010), Mike Newell's screen adaptation of Charles Dickens'Great Expectations (2012), with Helena Bonham Carter and Jeremy Irvine, and Wes Anderson's The Grand Budapest Hotel (2014).

He is also known for his roles in major film franchises such as the Harry Potter film series (2005-2011), in which he played the evil Lord Voldemort. Ralph also appears in the James Bond series, in which he has played M, starting with the 2012 film Skyfall (2012).

In 2011, Fiennes made his directorial debut with his film adaptation of Shakespeare's tragedy political thriller Coriolanus (2011), in which he also played the title character, opposite Gerard Butler and Vanessa Redgrave. Fiennes has won a Tony Award for playing Prince Hamlet on Broadway.

In 2015, Fiennes played a music producer in Luca Guadagnino's A Bigger Splash (2015), starring opposite Tilda Swinton and Matthias Schoenaerts, and in 2016, Fiennes starred in Joel and Ethan Coen's Hail, Caesar! (2016).

Since 1999, Fiennes has served as an ambassador for UNICEF UK.