Austin James (played by ): A genius-level scientist and inventor with eidetic memory, Austin is constantly thinking, inventing ground-breaking technology and seeking answers to various mysteries and problems. One disadvantage to his vast intellect is that it isolated him from his peers from a very early age. As a result, he is awkward and uncomfortable in normal social situations, and very reclusive. His manner can be at times overly brusque, but he has a deep love of humanity. Austin is occasionally called in by local police to investigate baffling homicides, though he professes to not understand the motivation for murder. He founded the think tank Serendip, but he has no interest in managing its day-to-day affairs, preferring to spend most of his time engaged in a variety of experiments and investigations at his "workshop," a refurbished warehouse which serves as his home and laboratory.

Michelle "Mickey" Castle (played by ): Mickey seems an unlikely candidate to serve as Austin James' secretary, as she lacks any background in science and relies more on her instincts instead of logic. Though she initially finds Austin's genius and eccentricities intimidating (and infuriating), Mickey comes to enjoy the adventure of working for him. Similarly, while Austin has fired every other secretary foisted upon him by Serendip, he is soon captivated by Mickey's uncanny knack for providing unique observations that help him in his investigations.

Howard Millhouse (played by ): As Serendip's long-suffering director, Howard constantly finds himself at wit's end, managing the company founded by Austin, and bankrolling his various experiments. Howard's attempts to draw Austin out of his warehouse to take a more active interest in his own company have only served to make Austin keep Serendip further at bay.

Graham McKinley (played by ): Howard's apparent successor at Serendip who also butts heads with Austin from time to time over various projects.

at IMDb