Reginald Hartwell was a 24th century former agent for the Department of Temporal Investigations (DTI) who later became the department's workaholic director. Hartwell was 52 years old at some point in the late 24th century and remained single but looking for a significant other. He kept his hair and moustache trimmed, and clothes "neat and presentable." He worked at the headquarters of DTI in London and lived nearby. Hartwell also had an eidetic memory and spoke Romulan, Vulcan and Federation Standard. He called DTI agents "the secret heroes of the Federation," and preferred the anonymity of DTI. Hartwell had a respect for the Temporal Prime Directive.