•
U.S. Navy Commander Francis "Frank" Bartholomew Parker (
Jonathan LaPaglia), a former
Navy SEAL and ex-
CIA operative recruited by the program to be the project's "chrononaut". While having served with distinction, he is not the program's initial choice due to a history of emotional instability stemming from an extended period of torture while being held prisoner in
Somalia; however, Donovan vouches for Frank, and facilitates his release from a secret mental health facility for troubled operatives with classified knowledge. Frank's testing reveals that in addition to the determination and physical stamina necessary to succeed as a Navy SEAL, he has an exceptionally high pain tolerance, a
photographic memory, and a capacity for unorthodox problem-solving. In addition to his military service, several plot elements focus on his troubled youth in
Philadelphia, his attempts to reconcile relationships with his ex-wife and estranged son, and his attempts to use time travel for personal gain. The latter is often played for comedic effect as a series of
running gags where his future knowledge of sports betting is rendered defunct due to changes in the timeline, and his romantic pursuit of Dr. Vukavitch succeed only to be undone when he travels through time. Throughout the series, he also clashes with the project's head of security, Nathan Ramsey, due to the restrictive nature of his service with the program. His codename in the field is "Conundrum." • Dr. Olga Vukavitch (
Justina Vail), a
Russian doctor who worked in the Russian version of the Backstep Project, which, without any technology from the Roswell crash, never reached operational level. She lost her husband in an accident. She grows to like Frank (whom she addresses formally) at times, but is almost invariably put off by some new show of his crassness or arrogance (although Frank often manages to overcome this, only to have to Backstep). Despite this, many episodes reveal that she has a hidden affection for Frank, and she always thinks of him shortly before she dies in a previous timeline. • U.S. Navy Captain Craig Donovan (
Don Franklin), Navy SEAL and Project Backstep's military advisor/tactical coordinator and backup chrononaut. He is an old friend of Frank's from the SEAL teams, who led the operation to rescue him in
Mogadishu. As a Chrononaut candidate, Donovan was an early lead during the testing phase, due to his excellent hand-eye coordination, physical conditioning, and psychological stability. Compared with Frank, the scientists believed that Donovan would be the better overall pilot for the chronosphere, and that his coordination would ensure less risk to the equipment; however, Talmadge eventually selects Frank due to the advantages of his pain tolerance and photographic memory, though Donovan never begrudges this and is Frank's strongest supporter. In spite of his 'backup' status, the series never depicts him taking Frank's place. He has, on occasion, assumed command of the project, its security forces, and the scientific branch during the end-of-the world situations that frequently precede a backstep as project leaders were killed or incapacitated. He is well-liked and respected by the scientific, security, and military staff and was Ramsey's preferred choice. • Dr. Bradley Talmadge (
Alan Scarfe), director of the Backstep Project operations and a long-time member of the NSA intelligence community. Although middle-aged, he is shown several times to still have excellent combat skills. •
NSA Agent Nathan Ramsey (
Nick Searcy), Backstep Project security chief. A short-tempered, highly opinionated man, he opposes Frank becoming chrononaut and is therefore made the prime target of Parker's practical jokes. Ramsey is portrayed to be conservative, and he always makes
politically incorrect statements supporting the use of force to quickly end problems (but the way he puts it is always funny instead of malicious). Ramsey's area of expertise is intelligence and counter-intelligence. His job is to use the information that Frank Parker gives him to avert disasters, but Frank commonly fulfills the missions himself. Ramsey is also the man the NSA sends out to retrieve Frank when the Ex-Seal makes unscheduled disappearances from the base. • Dr. Isaac Mentnor (
Norman Lloyd) (seasons 1–2, guest appearances in season 3), a scientist with a shadowy past that's tied into the Roswell cover-up, Dr. Mentnor was the man who initially conceived the Backstep project. • Dr. John Ballard (
Sam Whipple) (seasons 1–2). The wheelchair-using resident genius on the Backstep Project. Ballard is responsible for calibrating and maintaining the Spheres and keeping them active to allow for a quick Backstep if needed. • Andrew "Hooter" Owsley (Kevin Christy) (season 3). A young
physics prodigy whom Ballard suggested as his replacement. He works with Dr. Mentnor to enhance the existing Backstep technology and has been shown occasionally to have a secret crush on Olga. ==Production==