Jackson grew up in California until age 8, when his family moved back to Vancouver. Soon after he took up acting, landing a role in a commercial for Keebler's Potato Chips. He is best known for the role of Pacey Witter on Dawson's Creek, but he has also appeared in several popular movies, including Cruel Intentions, Apt Pupil, Scream 2 and The Skulls.
Joshua is left-handed and is around 6 feet tall. He is rumored to hold dual U.S./Canadian citizenship.