Louis Sebastian Theroux was born on 20 May 1970 in Singapore. He is the son of English mother Anne (née Castle) and American father Paul Theroux, a noted travel writer and novelist. His paternal grandmother, Anne Dittami, was an Italian-American grammar school teacher, while his paternal grandfather, Albert Eugène Theroux, was a French-Canadian salesman. Theroux holds dual British and American citizenship. He has an elder brother, Marcel, who is also a writer and TV presenter, and his cousin Justin Theroux is an actor and screenwriter.

Louis Theroux moved to England at the age of one and was raised in the Catford area of South London. He attended the prestigious Westminster School, where he formed friendships with future comedians Adam Buxton and Joe Cornish, as well as future Deputy Prime Minister Nick Clegg. He later pursued Modern History at Magdalen College, Oxford, graduating with first-class honours.

Louis graduated from Oxford in 1991 and got his break in television in 1994 working for American documentary maker Michael Moore, who hired him as a writer and correspondent on his show, TV Nation. He then went on to make the BAFTA-winning series Louis Theroux’s Weird Weekends, When Louis Met…, and a series of award-winning specials.

He founded Mindhouse Productions in 2019 and launched The Louis Theroux Podcast, which consistently tops UK charts. The family has lived between London and Los Angeles, although they spent much of the COVID-19 pandemic in London. Louis and Nancy have three children — Frederick, Albert, and Walter Theroux.