Justin Hartley (January 29, 1977) was born when his family was residing in Knoxville, Illinois, and born at the nearby hospital in Galesburg. He was raised in the Chicago suburb of Orland Park, with his brother Nathan, and sisters Megan and Gabriela. After graduating from Carl Sandburg High School, he attended Southern Illinois University Carbondale and University of Illinois at Chicago where he majored in history and theater.

Justin Hartley portrayed Fox Crane on the NBC daytime soap opera Passions from 2002 to 2006. In 2006, he played the starring role as Aquaman in a television pilot for The CW titled Aquaman (or Mercy Reef), but it was not picked up as a series. Hartley did a seven-episode run as billionaire Oliver Queen on the CW series Smallville later that year. In 2008, he returned to Smallville as a regular cast member, following the departures of Kristin Kreuk, Michael Rosenbaum, Laura Vandervoort, and John Glover. Hartley also co-wrote the 2010 episode “Sacrifice” and directed the 2011 episode “Dominion”. In 2008, he starred as Tom in the film Red Canyon, filmed in the badlands of Utah.

After Smallville, Hartley starred opposite Mamie Gummer in The CW comedy-drama Emily Owens, M.D., but the show was cancelled after one season. He also guest-starred on Chuck, Castle, and Hart of Dixie, and from 2013 to 2014, he had a recurring role as Victoria Grayson’s (Madeleine Stowe) illegitimate son, Patrick Osbourne, on the ABC primetime soap opera Revenge. In February 2014, Hartley landed the lead role of Tim opposite Anna Camp in the ABC comedy pilot Damaged Goods, but the show was never picked up to series. In March 2014, he was cast in a recurring role in the second season of the ABC drama series Mistresses as plastic surgeon Scott Trosman, a love interest for Josslyn Carver (Jes Macallan). In November 2014, Hartley took over the role of Adam Newman on the CBS daytime soap opera The Young and the Restless, and played the role until September 2016.

In 2015, it was announced that Hartley had been cast in a series regular role on the NBC drama series This Is Us, which debuted in September 2016. He and the cast won Outstanding Performance by an Ensemble in a Drama Series at the 24th Screen Actors Guild Awards. In 2017, he had a co-starring role in the comedy film A Bad Moms Christmas. In August 2020 Hartley signed on to star and executive produce a film adaptation of The Noel Diary, based on the novel of the same name.