From 1954 to 1959, Frears was educated at Gresham's School, a boarding independent school for boys (now co-educational) in the market town of Holt in Norfolk. This was followed by Trinity College, Cambridge, from 1960 to 1963.

At the University of Cambridge Frears was Assistant Stage Manager for the 1963 footlights Revue which starred Tim Brooke-Taylor, John Cleese, Bill Oddie and David Hatch. After graduating from the University, Frears worked as an assistant Director on the films Morgan! and if..... He spent most of his early directing career in television, mainly for the BBC but also for the commercial sector.

In the late 1980s, Frears came to international attention as a Director of feature films. His directorial film debut was the detective spoof Gumshoe (1971). His direction of My Beautiful Laundrette unexpectedly led to wider notice. The interracial gay romance, based on a Hanif Kureishi screenplay and shot on 16 mm film, was released theatrically in 1985 to great acclaim. It received an Academy Award nomination and two nominations for BAFTA Awards: it is known as the film that helped launch both Frears and actor Daniel Day Lewis.

Frears next directed the Joe Orton biopic Prick Up Your Ears, another collaboration with Playwright Alan Bennett. His second film adapted from a Kureishi screenplay was Sammy and Rosie Get Laid (1987). The following year, Frears made Dangerous Liaisons in France, with a cast that included Americans Glenn Close, John Malkovich, and Michelle Pfeiffer. Based on the late 18th-century French novel of romantic game playing, the film received numerous Academy Awards and BAFTA nominations. Frears was nominated for the BAFTA Award for Best Direction. Frears had further critical success with his next film The Grifters, another tale of con artists. The film earned Frears his first Academy Award nomination for best direction.

His 1992 film Hero, starring Dustin Hoffman, was a major box office disappointment. Frears was nominated for a Razzie Award for his direction of Mary Reilly.

Frears has also directed two films adapted from novels by Roddy Doyle, The Snapper (1993) and The Van (1996).

In 2006, Frears directed The Queen, about Queen Elizabeth II. It touched on the social strains caused by the people's mourning for the death of Princess Diana on 31 August 1997. The Queen also achieved immense critical acclaim, box-office success, and awards. Frears received his second Academy Award nomination for best direction, and Helen Mirren won numerous awards for playing the title role.

Frears' other films include Western The Hi-Lo Country (1998), which won him the best Director award at the Berlin Film Festival, High Fidelity (2000), which features a number of scenes where star John Cusack addresses the audience directly, Dirty Pretty Things (2002), and the British theatre comedy Mrs Henderson Presents (2005).

Frears returned to directing for television with The Deal (2003), which depicts an alleged deal between Tony Blair and Gordon Brown over which of them should become leader of the Labour Party in 1994.

His 2013 Irish adoption drama, Philomena, written by Jeff Pope and Steve Coogan, won the best screenplay award at the 2013 Venice Film Festival and the BAFTAS, and was nominated that year for Best Picture at the BAFTAs and the Academy Awards. It stars Coogan and Judi Dench. The same year, HBO released his television drama Muhammad Ali's Greatest Fight, which depicts the US Supreme Court deliberation over banning Muhammad Ali from boxing for refusing to serve in the Vietnam War.

He was one of several celebrities who endorsed the parliamentary candidacy of the Green Party's Caroline Lucas at the 2015 general election.