Sir Daniel Michael Blake Day-Lewis (born 29 April 1957) is an actor of dual English and Irish heritage. Often described as one of the greatest actors in the history of cinema, he is the recipient of numerous accolades, including three Academy Awards, four BAFTA Awards, three Screen Actors Guild Awards and two Golden Globe Awards. In 2014, Day-Lewis received a knighthood for services to drama.

Born and raised in London, Day-Lewis excelled on stage at the National Youth Theatre before being accepted at the Bristol Old Vic Theatre School, which he attended for three years. Despite his traditional training at the Bristol Old Vic, he is considered a method actor, known for his constant devotion to and research of his roles. Protective of his private life, he rarely grants interviews and makes very few public appearances.

Day-Lewis shifted between theatre and film for most of the early 1980s, joining the Royal Shakespeare Company and playing Romeo Montague in Romeo and Juliet and Flute in A Midsummer Night's Dream. Playing the title role in Hamlet at the  National Theatre in London in 1989, he left the stage midway through a performance after breaking down during a scene where the ghost of Hamlet's father appears before him—this was his last appearance on the stage. After supporting film roles in Gandhi (1982) and The Bounty (1984), he earned acclaim for his breakthrough performances in My Beautiful Laundrette (1985), A Room with a View (1985), and The Unbearable Lightness of Being (1988).

He earned three Academy Awards for Best Actor for his roles as Christy Brown in My Left Foot (1989), an oil tycoon in There Will Be Blood (2007), and Abraham Lincoln in Lincoln (2012). He was Oscar-nominated for In the Name of the Father (1993), Gangs of New York (2002), and Phantom Thread (2017). Other notable films include The Last of the Mohicans (1992), The Age of Innocence (1993), The Crucible (1996), and The Boxer (1997). He retired from acting twice, from 1997 to 2000, when he took up a new profession as an apprentice shoemaker in Italy, and from 2017 to 2024.