Watson was born in Bromley, South London. He started going to ballet lessons aged three with his twin sister and joined The Royal Ballet School aged 11. He graduated into The Royal Ballet in 1994 and was promoted to First Artist in 1998, Soloist in 2000, First Soloist in 2002 and Principal in 2005.
Watson's extreme flexibility has made him a muse for The Royal Ballet's Resident Choreographer Wayne McGregor and Artistic Associate Christopher Wheeldon. Role creations for McGregor include Symbiont(s), Qualia, Chroma, Infra, Carbon Life, Raven Girl and Tetractys – The Art of Fugue, and for Wheeldon Lewis Carroll/The White Rabbit (Alice's Adventures in Wonderland) and Leontes (The Winter's Tale). Watson has worked with numerous other contemporary choreographers, including Alastair Marriott, Ashley Page, Siobhan Davies, Arthur Pita and Cathy Marston, whom he has known from childhood. His repertory includes Romeo, Albrecht (Gizelle), Crown Prince Rudolf (Majerling), Des Grieux (Manon), Oberon (A Midsummer nights dream), Daphnis (Daphnis and Chloe), Ivan Tsarevich (Fire bird), Brighella (Pierrot Lunaire, chor. Glen Tetley), Arthur Troyte Griffith (Enigma Variations, chor. Frederick Ashton), Boy with Matted Hair (Shadowplay, chor. Antony Tudor), Messenger of Death (Song of the Earth, chor. Kenneth MacMillan), Woyzeck, Anubis (Sphinx, chor. Glen Tetley), Southern Cape Zebra ( ‘Still Life’ at the Penguin Cafe, chor. David Bintley), The Chosen One (The Rite of Spring, chor. Kenneth MacMillan), Brother (My Brother, My Sisters, Triad), Teacher (The Lesson) and roles in Gloria, Judas Tree, Anastasia, Images of Love, Symphonic Variations, Symphony in C, Four Temperaments, Agon, Stravinsky Violin Concerto, Afternoon of a Faun, Polyphonia, L’Invitation au voyage, Dances at a Gathering and Jewels (Emeralds) .
He created roles in Two-Part Invention, Cheating, Lying, Stealing, Sawdust and Tinsel, Hidden Variables, A Stranger’s Taste, Symbiont(s), This House Will Burn, Tryst, Qualia, Castle Nowhere, Chroma, DGV: Danse à grande vitesse, Seven Deadly Sins, Electric Counterpoint, Infra, Acis and Galatea (Royal Opera). He is a Diploma winner of the Benois de la Danse (2007, 2013).