Thomas william Hiddleston was born on 9 February 1981 in Westminster, London, the son of Diana Patricia (née Servaes) Hiddleston, an arts administrator and former stage manager, and James Norman Hiddleston, a physical Chemist. His father is from Greenock, Scotland and his mother is from Suffolk. His younger sister, Emma, is also an Actress, whilst his older sister, Sarah, is a Journalist in India. Through his mother, he is a great-grandson of Vice Admiral Reginald Servaes and a great-great-grandson of food Producer Sir Edmund Vestey.

While still doing student plays, Hiddleston began appearing on television, landing parts in Stephen Whittaker's adaptation of Nicholas Nickleby (2001) for ITV, the BBC/HBO co-production Conspiracy (2001), and as Randolph Churchill, the son of Winston Churchill, in the BBC/HBO drama The Gathering Storm (2002).

At the age of 13, Hiddleston began boarding at Eton College. He continued on to Pembroke College at the University of Cambridge, where he earned a double first in Classics. During his second term at Cambridge, he was seen in a production of A Streetcar Named Desire by talent agent Lorraine Hamilton of Hamilton Hodell. He proceeded to study acting at the Royal Academy of Dramatic Art, from which he graduated in 2005.

Hiddleston was the voiceover for BBC's documentary on the Galapagos Island in 2006. He also narrated the audiobook The Red Necklace by Sally Gardner in 2007, Hiddleston played the leading role of Edward in Hogg's second feature, Archipelago (2010). His TV credits include Magnus Martinsson in the BBC detective drama Wallander (2008), Bill Hazledine in Suburban Shootout (2006), John Plumptre in the BBC costume drama TV film Miss Austen Regrets (2008) and william Buxton in the BBC drama series Return to Cranford (2009). In 2007, he joined a list of British actors, including Kate Winslet and Orlando Bloom, to have guest starred in the long-running medical drama Casualty.

In November 2010, Hiddleston appeared with Benedict Cumberbatch, Gemma Arterton, Eddie Redmayne and Rose Byrne among others in Danny Boyle's one time production of The Children's Monologues, in which he played Prudence, a young girl upset with her mother for her father leaving and excited for her birthday. The play was a one time event of adapted stories of children's first-hand experiences in South Africa being re-interpreted by and performed by various actors.

In 2011, Hiddleston portrayed Novelist F. Scott Fitzgerald in writer-director Woody Allen's Midnight in Paris. He then played the noble Captain Nicholls in War Horse, a film based on the 1982 novel by Michael Morpurgo, directed by Steven Spielberg. The same year he starred as Freddie Page, a RAF pilot in the drama The Deep Blue Sea, alongside Rachel Weisz. In 2012, he reprised his role as the supervillain Loki in The Avengers. While filming a scene with Chris Hemsworth, who plays Thor, the film's Director, Joss Whedon told the fighting duo that the scene did not look real enough, so Hiddleston told Hemsworth to really hit him for the fight scene. "I said to Chris, 'Dude, just hit me. Just hit me because I'm protected here and it's fine.' He's like, 'Are you sure?' I was like, 'Yeah, it will look great. Just go for it.'" He provided the voiceover the Ancient Egyptian Book of the Dead in 2011 and poetry for iF Poems and The Love Book on iTunes in 2012.

On television in 2012, Hiddleston appeared in the BBC Two series The Hollow Crown, portraying Prince Hal opposite Jeremy Irons as Henry IV in the adaptation of Shakespeare's Henry IV, Part I and Part II. He later as appeared as King Henry V in the television film Henry V. In 2013, Hiddleston played Loki again in Thor: The Dark World, following which he played a vampire in Jim Jarmusch's film Only Lovers Left Alive with Tilda Swinton and Mia Wasikowska.

In late 2013 and early 2014, Hiddleston starred as the title character in the Donmar Warehouse production of Coriolanus, winning the Evening Standard Theatre Award for Best Actor. In 2015, he starred in Guillermo del Toro's Crimson Peak, Ben Wheatley's High Rise, and played the troubled country music singer Hank Williams in the biopic I Saw The Light.

Hiddleston lives in the Belsize Park area of north-west London. He was one of the celebrities (alongside Benedict Cumberbatch, E. L. James and Rachel Riley, among others) to design and sign his own card for the UK-based charity the Thomas Coram Foundation for Children. The campaign was launched by crafting company Stampin' Up! UK and the cards were auctioned off on eBay during May 2014. He is also a UK ambassador of the humanitarian and developmental assistance fund group UNICEF. He travelled to Guinea in early 2013 to help women and children and raise awareness about hunger and malnutrition. Hiddleston is a self-described feminist.

Hiddleston was one of the narrators in the 2015 documentary Unity directed by Shaun Monson. Hiddleston appeared as Jonathan Pine in the 2016 television mini-series The Night Manager based on the espionage and detective novel of the same name by John le Carré. The series started filming in Spring 2015 and aired on BBC and AMC with Hugh Laurie also starring.

Hiddleston won the light-hearted UK award Rear of the Year 2016, in which the public nominate the male and female UK-based celebrities that they think should win the titular award. One of the highest profile actors in contemporary British popular culture, Hiddleston appeared on Debrett's 2017 list of the most influential people in the UK.

In 2017, Hiddleston starred in Legendary Pictures' King Kong film, Kong: Skull Island. It was released on 10 March, and was directed by Jordan Vogt-Roberts. He reprised his role as Loki in Thor: Ragnarok, released on 3 November 2017, and will also appear in Avengers: Infinity War (2018) and its as yet untitled sequel (2019).