Niarchos is an avid art collector. He was the anonymous buyer of Jean-Michel Basquiat's 1982 Self-Portrait, which he paid $3.3 million at Christie's November 12 contemporary auction. The astonishing price is about five-and-a-half times what any Basquiat painting has previously brought at a public sale.
Philippe owns his late father's art collection. Among its trophies are Pablo Picasso's self-portrait Yo, Picasso, which Niarchos pere bought in 1989 for $47,850,000, and Vincent van Gogh's Self-Portrait with Bandaged Ear, probably worth around $90 million. It also includes Andy Warhol's Shot Red Marilyn, which he bought in 1994 at Christie's New York for $3.63 million. Andy Warhol's skull portraits are from Philippe's CAT scan. Warhol completed these works in 1985, using silkscreens made from CAT-scan films of the skull of Philip Niarchos, who commissioned the artist to paint his portrait.
Philippe is mentioned throughout Andy Warhol's Diaries. Andy shares details of Philippe's relationship with socialite, Barbara Allen and their dysfunctional relationship.
He married thirdly 1984 (divorced) Victoria Christina Guinness (b. 30 January 1960), daughter of Patrick Benjamin Guinness (of the non-aristocratic younger branch of that well-known family and granddaughter of the socialite Gloria Guinness. Her half-uncle was the Aga Khan IV. They have had two sons and two daughters.