Dev Patel was born on 23 April 1990 in Harrow, the son of Anita, a care worker, and Raj, an IT consultant. His parents are Indian Hindus, though they were both born in Nairobi, where there is a significant Indian community; they emigrated to England separately in their teens, and first met in London. Patel was raised in the Hindu faith. He grew up in the Rayners Lane district of Harrow and attended Longfield Middle School. Patel had his first acting role as Sir Andrew Aguecheek in the school's production of Twelfth Night. He was given the Best Actor award for his performance.
Patel later attended Whitmore High School, receiving an A* in GCSE Drama for his "self-penned portrayal of a child in the Beslan school siege". His drama teacher Niamh Wright has stated, "Dev was a gifted student who quickly impressed me with his innate ability to communicate a wide variety of characters imaginatively and creatively. He was awarded full marks for his GCSE performance to a live audience and the visiting examiner was moved to tears by his honest portrayal." He completed his AS Levels in PE, Biology, History, and Drama in 2007 at Whitmore High School while working on Skins.
Patel said that he was "bloody energetic" as a child, and used to get in trouble at school because of it. He started training at the Rayners Lane Academy of Taekwondo in 2000. He competed regularly in both national and international championships, including the 2004 AIMAA (Action International Martial Arts Association) World Championships in Dublin, where he won a bronze medal. The World Championships took place in October 2004, when he was a red belt competing in the junior division against other red and black belts. He made it to the semi-finals, where he lost to Irish black belt Niall Fitzmaurice in "a very close and tough fight", and ended up winning a bronze medal. He later gained a 1st dan black belt in March 2006.
In 2006, Patel began his acting career when he auditioned for the E4 teen drama television series Skins. Patel's mother saw the casting ad in a newspaper and took him to the audition even though he had a science exam the next day. After two auditions, he was cast in the role of Anwar Kharral, a British Pakistani Muslim teenager. The characterisation of Anwar was partly based on Patel's personality and the role was written specifically for him after he was cast in Skins. Patel, who had no professional acting experience, said that on "the first day of shooting I didn't really know what to do."
The first series of the show aired in January 2007 and went on to win the Rose d'Or for Drama in 2008 and receive a nomination for Best Drama Series at the 2008 BAFTA Television Awards. Patel reprised his role as Anwar for the second series of Skins, which aired in February 2008. The second series of Skins won the Philips Audience Award at the 2009 BAFTA Television Awards.
Patel made his feature film debut when he was cast in the role of Jamal Malik, the central character in Danny Boyle's film Slumdog Millionaire. The character Jamal Malik is an Indian Muslim boy born and brought up in the poverty of Bombay, India. Boyle considered hundreds of young male actors, but found that Bollywood leads were generally "strong, handsome hero-types", not the personality he was looking for. Boyle's 17-year-old daughter Caitlin pointed him to Skins.
After five auditions for the role, the actor was eventually cast in August 2007. The film's producer found the original choice for the lead role, Ruslaan Mumtaz, too good looking for the role. Boyle said, "I wanted a guy who didn't look like a potential hero; I wanted him to earn that in the film." To prepare for the role, Patel went along with Boyle while scouting for filming locations, where he was able to observe the Dharavi slums for himself. He also worked at a call centre for a day and in a hotel, where he washed dishes.
After the release of Slumdog Millionaire at the end of 2008, Patel went on to receive a number of awards for his performance, including a British Independent Film Award, National Board of Review (NBR) Award, Chicago Film Critics Association Award, and two Black Reel Awards for Best Actor and Best Breakthrough Performance. Patel was also nominated for Best Supporting Actor at the 2009 Screen Actors Guild (SAG) Awards. The award eventually went posthumously to Heath Ledger for his performance in The Dark Knight, though Patel did win the Screen Actors Guild Award for Outstanding Performance by a Cast in a Motion Picture, which he shared with ten other cast members from Slumdog Millionaire. On 8 January 2009, Patel won the Critics' Choice Award for Best Young Performer. He was also nominated for two London Critics Circle Film Awards, the NAACP Image Award for Outstanding Supporting Actor, the 2009 BAFTA Award for Best Leading Actor, and European Film Award for Best Actor. The film itself won four Golden Globes, including Best Drama Film, and eight Academy Awards, including Best Picture.
Patel played Zuko in M. Night Shyamalan's The Last Airbender, a feature film adaptation of the animated series Avatar: The Last Airbender, which was released 1 July 2010 to extremely negative reviews. Despite being a commercial success, the film was a critical failure and Patel even received a Razzie Award nomination as Worst Supporting Actor that year, although his role was well received, and was considered by many to be one of the film's positive aspects.
Patel later starred in the short film The Commuter, which was directed by the McHenry Brothers to promote the Nokia N8 smartphone in the U.K. Fans who won a Nokia UK run competition starred alongside Dev Patel in the short film. Patel co-starred in The Best Exotic Marigold Hotel (2012), directed by John Madden, with Judi Dench, Bill Nighy and Maggie Smith, which received positive reviews from critics and was a box office success, grossing $136 million. For the role, he had to take lessons in perfecting an Indian-English accent, as his native English accent was so strong.
From 2012 to 2014, Patel had a supporting role in the 2012 HBO television series The Newsroom as Neal Sampat, blogger for news anchor Will McAvoy. He also appeared alongside James Franco and Heather Graham in About Cherry, which premiered at the 2012 Berlin International Film Festival.
In 2014, Patel starred alongside Robert Sheehan and Zoë Kravitz in the film, The Road Within, about three unlikely friends, one with Tourette's syndrome (Sheehan), one with OCD (Patel) and an anorexic woman (Kravitz) who go on a road trip. The film received generally mixed reviews. Variety had positive words for the "bristling and committed performances by Robert Sheehan, Dev Patel and Zoe Kravitz" while noting that "there remains a nagging tidiness to the whole endeavor that leaves a strained, cloying aftertaste" that kept the movie from truly succeeding.
In 2016, Patel starred as Saroo Brierley in the biographical film Lion, directed by Garth Davis and co-starring Nicole Kidman and Rooney Mara, which premiered to rave reviews and "Oscar buzz" at the 2016 Toronto International Film Festival. The film is based on the non-fiction novel written by Brierley titled A Long Way Home. Patel won the BAFTA awards for 'Best Supporting Actor'. At the 89th Academy Awards, he was nominated for Best Supporting Actor for Lion.
He began dating his Slumdog Millionaire co-star Freida Pinto in 2009. On 10 December 2014, the couple announced that they had split after nearly six years of dating.