Tomlinson studied with Patrick McGuigan at the Royal Northern College of Music and with Otakar Kraus. He sings regularly with the Royal Opera and English National Opera, and has appeared with all the major British opera companies. He has sung at the Bayreuth Festival in Germany every year from 1988 to 2006, as Wotan, the Wanderer, King Marke, Titurel, Gurnemanz, Hagen and the Dutchman. In 2008, he created the title role in Harrison Birtwistle's opera The Minotaur at the Royal Opera House.
Tomlinson was made a Commander of the Order of the British Empire (CBE) in 1997 for his services to music and was knighted in the 2005 Queen's Birthday Honours List.
In 2014 he was awarded the Gold Medal of the Royal Philharmonic Society.