Stewart Peart was a human male in the 24th century. He was raised in England, and developed an interest in history at an early age. As a boy he dreamt of time travel, and as a young man, attended Starfleet Academy, despite only minor interest in space exploration, and difficulties with xenosociology coursework. His aptitude test scores guided him to the Federation Department of Temporal Investigations, and he was made an agent in 2376.

As his first assignment, Peart was assigned by Special Agent Marion Dulmur to escort Lieutenant Arex Na Eth, recently displaced from 2305 to 2376, to his dying father's home. Unfortunately, Peart mistook Arex for an Edoan rather than a Triexian, creating a nearly tragic delay in his return to his homeworld. They did eventually reach Triex, and Arex promised him a positive report to Dulmur. (NF short story: "The Road to Edos")

Despite appearing to be a perpetually flustered rookie in 2381, Peart was one of the few humans to last five years as a DTI agent.

On 17 January 2382, Peart was to have gone on a date with fellow agent Teresa Garcia but she had to cancel it due to a mission. (ST novel: DTI: Watching the Clock)