Samuel Preston was born in Worthing, West Sussex. He was educated at Sompting Abbotts prep school and Bishop Luffa School. He is son to Anthony and Miranda Preston (born in Philadelphia), and brother to Alex and Lucy Preston. His grandfather is the Princeton University English professor Samuel Hynes. His brother, Alex Preston, is a novelist. In his teenage years Preston lived in Philadelphia with his mother's side of the family.
Preston became the lead singer of Worthing-based pop group, The Ordinary Boys. They had a string of top-ten hits in the UK Singles Chart. Their most famous song, "Boys Will Be Boys", featured in the 2007 film Harry Potter and the Order of the Phoenix.
After The Ordinary Boys split, Preston started working on material for a solo album, and released the song "Dressed to Kill", on 5 July 2009 as part of T4. The song samples the introduction from the song "Happy House" by Siouxsie and the Banshees. The single was released on 7 September 2009 but failed to chart after Preston had to delay the launch and pull out of promotional performances after breaking both arms in a bicycle accident. He is now a songwriter. In 2011, Preston co-wrote the number one Olly Murs song "Heart Skips a Beat". Preston announced the reforming of the Ordinary Boys in 2011, and a new 12-date tour. Preston also co wrote the song and duet "Beautiful" by Enrique Iglesias and Kylie Minogue for their respective albums, and his track "Dressed to Kill" was re-recorded by American singer Cher for her album Closer to the Truth.
In January 2006, Preston appeared on Channel 4's fourth series of Celebrity Big Brother. During his time in the house he became close to the eventual winner, Chantelle Houghton. Preston was evicted during the final episode on 27 January 2006, finishing in fourth place.
In 2007, Preston filmed a documentary on voodoo for Channel 4. He has also presented Top of the Pops and CD:UK.
In January 2007, Preston appeared as a guest panellist on comedy gameshow Never Mind the Buzzcocks. He walked out of the studio during the programme's recording, offended by jokes made at Houghton's expense by the show's host Simon Amstell. He later regretted this, reflecting to the BBC "I'm struggling to think why I would have acted so weird." Speaking of Amstell, Preston said he is "funny, charming and likeable, which made it [walking off] all the more embarrassing".
On 24 August 2010 he returned to the Big Brother franchise for Ultimate Big Brother, along with his now ex-wife Chantelle; he finished sixth.
A week after the end of Celebrity Big Brother, Preston became engaged to his longtime French girlfriend, Camille Aznar. He kept in contact with Houghton from the Big Brother show, and broke up with Aznar a month later to allow Houghton to move into his Brighton flat. He and Houghton got engaged on 11 April 2006 and, in an exclusive £300,000 each deal with OK! magazine, they were married on 25 August 2006 at Dartmouth House in Mayfair, London.
After their honeymoon, the couple moved to Preston's flat in Brighton, East Sussex.
Preston and Houghton announced their separation on 27 June 2007, and received the decree nisi for their divorce on 21 November 2007.
Preston moved to Philadelphia in 2008, where he lived for 3 years. He had American citizenship from his mother's side of the family.
As of 2016 Preston is dating 23 year old model and TV industry worker Emily Smith, a graduate of King's College London.