Notable for his art history scholarship, he is most famous for his multi-volume, Whitbread Award-winning biography A Life of Picasso. His other works include Sacred Monsters, Sacred Masters: Beaton, Capote, Dali, Picasso, Freud, Warhol, and More (2001) and The Sorcerer's Apprentice: Picasso, Provence, and Douglas Cooper (1999).
After studying at the Slade School of Fine Art, he wrote reviews for The New Observer and also worked as a designer.
In the early 1960s, he staged a major Pablo Picasso retrospective exhibition in New York City.
He and his two younger siblings grew up in London as the children of Sir Wodehouse Richardson and Patty Crocker Richardson. During the 1950s, he had a lengthy relationship with fellow art historian Douglas Cooper.
Richardson penned a 2009 work titled Warhol from the Sonnabend Collection, as well as several other books focusing on American pop artist Andy Warhol.