Anecdotes

Guest-starred in four episodes of Parks and Recreation (2009), as the love interest of Leslie Knope (played by Amy Poehler). In one episode, Knope wistfully wishes she could "reunite soulmates" such as Brad Pitt and Jennifer Aniston. Ironically, Theroux and Aniston were married five years later.

Became engaged to Jennifer Aniston on his birthday, August 10, 2012.

Cousins are Marcel Theroux, a writer and Louis Theroux, the actor, writer and journalist who makes television programs for the BBC.

Academy Award-nominee (documentaries) Rachel Grady and her friend, Brooke Jones, took Justin Theroux to his first prom in Washington, D.C. and Justin's journalist mother, Phyllis Theroux, reported on their date in the June 5, 1985 New York Times.

Has a younger brother, Sebastian, born in 1989

Nephew of Paul Theroux, author of many travel books.

His father is of half French-Canadian and half Italian descent. His mother has English, German, 1/64th Spanish, and distant Dutch, ancestry.

Engaged to actress Nicole Brydon Bloom (Sept. 1, 2024).