Previously, he served as a producer and director on the series from Seasons 2-7, including the television movie "24: Redemption." He'll be back for its upcoming return, "24: Live Another Day."
Cassar will executive-produce and direct multiple episodes on the 12-episode season, including the first two episodes. Cassar reunites with executive producers Howard Gordon and David Fury on the limited-run series.
During the network's upfront presentation in May, Fox entertainment chairman Kevin Reilly said the limited series will feature only the most eventful hours in a new Jack Bauer (Kiefer Sutherland) adventure.
The network plans to use "24" to help launch another limited-run series, M. Night Shyamalan's "Wayward Pines."
“I'm very happy to be renewing my relationship with the 20th Century Fox TV and Imagine family and am excited to call ‘action!’ again on the set of the resurrected ’24,’" Cassar said in a statement. "Considering I was not involved in Season 8, this new ’24’ event series gives me the chance for closure on a show that is very important to me."
“Jon was a profoundly integral part of ’24’ creatively and culturally. It doesn’t feel like it would be ’24’ without him, and we’re all just really thrilled to be working with him again,” Gordon said.
Cassar has won two Emmys and a DGA Award for his work on the series. His other producing credits include "Continuum," "Person of Interest," "Revolution," "Terra Nova" and "Fringe." He also directed and produced the Emmy-winning miniseries "The Kennedys," which also garnered him a DGA award.