- The Bauer family, played by Kiefer Sutherland, Leslie Hope and Elisha Cuthbert were all either born or raised in Canada.

- Jack Barrett was the initially the planned name for Kiefer Sutherland’s character.

- Sarah Clarke (Nina Myers) had to wear her own clothes for the entire first season, due to only being cast on the morning shooting began for the first-ever episode.

- Reiko Aylesworth originally auditioned for both the parts of Nina Myers and Kate Warner, before being cast as Michelle Dessler.

- Mary Lynn Rajskub (Chloe O'Brian) is a stand-up comedian and when she's not acting, performs at L.A. comedy clubs.

- As a child, Kim Raver (Audrey Raines) appeared in Sesame Street.

- Two episodes are filmed simultaneously over a period of 15 days.

- All cast members are required to have their hair trimmed every five days.