Newell was born in St Albans, Hertfordshire, the son of amateur actors. Newell was educated at St Albans School and Magdalene College, Cambridge. He then attended a three-year training course at Granada Television, with the intention of entering the theatre.
Newell directed various British TV shows from the 1960s onwards (such as Spindoe, credited as Cormac Newell, and Big Breadwinner Hog), but eventually shifted his focus to film direction.
His first feature-length project was The Man in the Iron Mask (1977), a made-for-television film. His first critically acclaimed movie was Bad Blood (1982), concerning the 1941 manhunt for the New Zealand mass-killer, Stan Graham, played by Jack Thompson. This was followed by Dance with a Stranger (1985), a biographical drama starring Miranda Richardson as Ruth Ellis, the last woman to be hanged in Great Britain. For his directorial efforts, Newell won the Award of the Youth at the 1985 Cannes Film Festival.
Newell continued his successes in the film industry with Enchanted April (1992), an adaptation of the 1922 novel by Elizabeth von Arnim. Miranda Richardson received a Golden Globe for Best Actress in a Comedy/Musical and Joan Plowright won a Golden Globe for Best Supporting Actress in a Comedy/Musical.
During this period, George Lucas recruited Newell as one of the numerous feature film directors to direct episodes of The Young Indiana Jones Chronicles.
The comedy Four Weddings and a Funeral (1994) was also critically acclaimed – it won numerous awards, including a César Award (Best Foreign Film), a Golden Globe (Best Actor – Hugh Grant), and a number of London Critics Circle Film Awards (Best Director, Film, Producer, and Screenwriter).
Since these award-winning productions, Newell has directed a number of films in Hollywood, such as Donnie Brasco (1997) (starring Al Pacino and Johnny Depp), Pushing Tin (1999) (starring John Cusack, Billy Bob Thornton, Cate Blanchett, and Angelina Jolie) and Mona Lisa Smile (2003) (starring Julia Roberts, Kirsten Dunst, and Julia Stiles).
In 2005, Newell was presented with an honorary degree of Doctor of Arts by the University of Hertfordshire which has a campus in St Albans, his birthplace. He was also awarded the BAFTA Britannia Award for Artistic Excellence in Directing for his career prior to 2005. Newell became the first British director of the Harry Potter film series with the production of Harry Potter and the Goblet of Fire, the fourth adaptation in the series, which became a major critical and financial success worldwide. Newell is heard briefly as the radio announcer at the beginning of the film.
Newell directed Love in the Time of Cholera in 2007 and Prince of Persia: The Sands of Time in 2010. In February 2011, Newell attended the British Academy Film Awards along with Harry Potter author J. K. Rowling, David Heyman, David Barron, David Yates, Alfonso Cuarón, Rupert Grint, and Emma Watson to collect the Michael Balcon Award for Outstanding Contribution to British Cinema on behalf of the Harry Potter film series.
Continuing to work on adaptations, Newell directed Great Expectations (2012) from the novel by Charles Dickens, with Ralph Fiennes, Helena Bonham Carter, and Jeremy Irvine in starring roles. The film had its world premiere at the Toronto International Film Festival.The Man in the Iron Mask (1977)
The Awakening (1980)
Bad Blood (1981)
Dance with a Stranger (1985)
The Good Father (1985)
Amazing Grace and Chuck (1987)
Enchanted April (1992)
Into the West (1992)
The Young Indiana Jones Chronicles (1993)
"Istanbul, September 1918"
"Florence, May 1908"
Four Weddings and a Funeral (1994)
An Awfully Big Adventure (1995)
Donnie Brasco (1997)
Pushing Tin (1999)
Mona Lisa Smile (2003)
Harry Potter and the Goblet of Fire (2005)
Love in the Time of Cholera (2007)
Prince of Persia: The Sands of Time (2010)
Great Expectations (2012)
The Interestings (2016)