He starred as Thranduil the Elvenking in The Hobbit trilogy and as Joe MacMillan in the period drama television series Halt and Catch Fire.

[4] As a child, Pace spent several years in Saudi Arabia, where his father worked in the oil business; the family later moved to Houston, Texas.

[5] Pace attended Klein High School in Spring, Texas, a suburb of Houston, with actor Matt Bomer.

Pace briefly stopped attending high school to act at Houston's Alley Theatre before returning to graduate.

In 1997, he was accepted by the Juilliard School's Drama Division as a member of Group 30 (1997–2001), which also included actors Anthony Mackie and Tracie Thoms.

He also starred in a production of Craig Lucas's Small Tragedy, for which he was nominated for a Lucille Lortel Award as Outstanding Actor.

Pace made his Broadway debut in Larry Kramer's play The Normal Heart, portraying Bruce Niles.

[15] Stephenie Meyer, the author of the Twilight saga, was very satisfied with Pace's performance as Garrett, since he "stood out as someone who really was just so much fun and really looked the part.

[19] On April 30, 2011, it was announced that Pace had been cast as the king of the Mirkwood Elves, Thranduil, in Peter Jackson's film adaptation of J. R. R. Tolkien's The Hobbit.

The announcement was made by Peter Jackson himself, who revealed on his Facebook page that Pace had been his favorite for the part, ever since he saw his performance in The Fall.

[21][22] On July 28, 2011, it was announced that Pace had been cast in Steven Spielberg's Lincoln, as the one-time New York City mayor Fernando Wood, an early Confederate supporter.

[33] In 2018, Pace was cast as Sam Colin in Hong Kong action crime television series Flying Tiger 2 produced by Shaw Brothers Studios.

[34] In 2019, Apple announced that Pace had joined the cast of its adaptation of Isaac Asimov's Foundation, which premiered in September 2021, playing the role of Brother Day, the Galactic Empire's current Emperor.

[35] Pace was the narrator of the horror podcast entitled Darkest Night, which was produced by the Paragon Collective and AMC's streaming service Shudder.

[36][37] Pace's sexual orientation became a topic of public discussion after he was accidentally outed as gay by Ian McKellen, who worked with him in The Hobbit films, in 2012.