Courtney was born in Monterey, California, on January 31, 1996, and lives in Moscow, Idaho. While still living in Idaho, Courtney took a trip to Los Angeles during the first week of his summer school break in 2010, where he hoped to be in a commercial and make $100.
Casting director Patti Kalles advised Courtney to audition for Paramount Pictures' Super 8, co-produced, written and directed by J. J. Abrams and produced by Steven Spielberg and Bryan Burk. After 11 callbacks, Courtney landed the starring role of Joseph "Joe" Lamb in the film.
The movie was released on June 10, 2011 and centers around a group of kids who are forced to deal with strange happenings in their small town. On July 26, 2012 he won a Saturn Award for Best Performance by a Younger Actor for his role in Super 8.
In August 2011, Courtney filmed Tom Sawyer & Huckleberry Finn in Bulgaria, an adaptation of Mark Twain's classic. Courtney portrays Tom Sawyer alongside Val Kilmer as Mark Twain, Jake T. Austin as Huckleberry Finn, Katherine McNamara as Becky Thatcher, and Noah Munck as Ben Rogers. Written and directed by Jo Kastner, the film was produced by Weinhart and Kastner.
Alongside Isabelle Fuhrman (Orphan), Courtney completed filming the supernatural thriller The Between. In the film, the young actor plays a disgruntled teen who joins his father on a camping trip only to have a run-in with otherworldly forces. Filming was shot from September to October 2011 in North Carolina. The Between had its world premiere at the Brussels International Fantastic Film Festival on April 6 in the main theater of the Bozar.
In the Spring of 2012, Courtney filmed a Fox TV movie entitled Rogue, which was directed by Brett Ratner.
In November 2012, Courtney was cast in the Stephen King film Mercy, produced by Blumhouse Productions and released by Universal Studios. Mercy filmed in Simi Valley, California, from January to February 2013, and was released to DVD and VOD on October 7, 2014.
In April 2013, Courtney was cast in the indie film Dear Eleanor. It is a coming of age story about two best friends (Isabelle Fuhrman and Liana Liberato) traveling across the U.S. in 1962 to meet their childhood hero, Eleanor Roosevelt. The film was produced by Leonardo DiCaprio's Appian Way Productions.
In July 2013, Courtney was cast in the indie film Sins of our Youth. The story is about four teenage boys who accidentally kill a young boy while recreationally shooting assault rifles. Courtney stars alongside Lucas Till (X-Men) and Ally Sheedy (The Breakfast Club). Sins of Our Youth filmed in August 2013 in Las Vegas.
In February 2014, Courtney was cast in the CW Television Network pilot The Messengers, which centers on a mysterious object that crashes down to Earth and a group of seemingly unconnected strangers die from the energy pulse. They then awaken to learn that they have been deemed responsible for preventing the impending apocalypse. Courtney stars alongside Shantel VanSanten (One Tree Hill), Diogo Morgado (Son of God), Sofia Black D'Elia (Skins), and J. D. Pardo (Revolution).
In August 2014, Courtney filmed the indie project The River Thief in Lewiston, Idaho. Courtney stars alongside American country singer-songwriter Tommy Cash, Paul Johansson (One Tree Hill), and Bas Rutten.
In October 2015, Courtney was cast the indie film "Replicate" in Jackson, Mississippi. Courtney stars alongside Cam Gigandet and Calum Worthy. "Replicate" is in post-production and is scheduled for release in July 2016.
In April 2016, Courtney was cast in the indie film "F*&% the Prom" in Los Angeles, California. Courtney stars alongside Danielle Campbell (The Originals) and Cameron Palatas (Pass the Light). "F*&% the Prom" is in post-production and is scheduled for release in 2017.