Main characters • Sheriff Jack Carter, portrayed by
Colin Ferguson, is a U.S. Marshal who reluctantly ends up as the sheriff of Eureka. Jack is consistently dumbfounded by the wonders Eureka produces, as well as its propensity to produce things that often threaten the entire town (or world). Despite being a man of average intelligence in a town full of geniuses, Jack's admittedly simple ideas and his intuition often save the day. • Zoe Carter, portrayed by
Jordan Danger (seasons 1–3, recurring in seasons 4–5), is Jack's rebellious teenage daughter. Unlike her father, she is intelligent enough to keep up with the town's residents. Yet, like her father, she also possesses
street smarts, something lacking for most of the town's residents. She hopes to attend
Harvard Medical School and become a physician and later does due to the alternate timeline. • Dr. Allison Blake, portrayed by
Salli Richardson-Whitfield, is a Department of Defense agent who acts as the liaison between Global Dynamics and the federal government in season one. Later, she becomes the head of Global Dynamics. Allison, unmarried, is mother of Kevin, who has
autism, but is shown to have improved symptoms in an alternate timeline (apparently attributable to high-tech cranial implants). • Dr. Henry Deacon, portrayed by
Joe Morton, is the town
jack of all trades and a brilliant scientist. Henry has ethical objections to the kind of research conducted at Global Dynamics, so he prefers to be employed as the town's mechanic. Henry's assistance is often invaluable in defusing the bad situations that are created by experiments at Global Dynamics. • Dr. Jim Taggart, portrayed by
Matt Frewer, is a somewhat eccentric animal expert. He works in
geophysics. • Vincent, portrayed by
Chris Gauthier, is the owner of Cafe Diem. • Dr. Nathan Stark, portrayed by
Ed Quinn (seasons 1–3), is one of Eureka's top scientists. He and Jack are frequently at odds, although both respect each other. On and off, he is romantically involved with Allison. He is modeled after
Tony Stark, a Marvel Comics character. • Dr. Beverly Barlowe, portrayed by
Debrah Farentino (seasons 1–2, recurring in seasons 4-5), is the town psychiatrist. She secretly works for a mysterious organization known as the Consortium, which has expressed a desire to exploit Eureka's innovations by whatever means necessary. • Josephina "Jo" Lupo, portrayed by
Erica Cerra (recurring in seasons 1–2, regular in seasons 3–5), is Eureka's deputy sheriff. She is a former
U.S. Army Ranger with a love of firearms. • Dr. Douglas Fargo, portrayed by
Neil Grayston (recurring in seasons 1–2, regular in seasons 3–5), is a junior scientist, treated somewhat dismissively by his peers. Accident-prone, he often ends up a victim of the disasters befalling the town, and has caused a fair share of the problems. Grayston also provides the voice of S.A.R.A.H. (Self Actuated Residential Automated Habitat), the
bunker home Jack and Zoe Carter live in. • Zane Donovan, portrayed by
Niall Matter (recurring in season 2, regular in seasons 3–5), is a rebellious genius who is recruited to Global Dynamics. He allegedly caused a stock market crash, and agreed to work for GD as an alternative to imprisonment. • Dr. Grace Monroe, portrayed by
Tembi Locke, (seasons 4–5) a scientist, mechanic, and wife of Henry Deacon in an alternate timeline created after the Eureka Five time-traveled to 1947. ==Episodes==