Within the TV show, Frank is one year older than his brother, Joe Hardy (1977 TV); his mother is dead, and Aunt Gertrude lives with the family to help raise the boys. He's the one most likely to take the lead in any investigation, and often is the one to instigate the brothers looking into a case. Joe calls him "cool and objective", but Frank also has a decided angry dark side, threatening to kick a woman's teeth in during one episode and punching Joe out during the third season premier, "Last Kiss of Summer". He holds a private pilot's license, is a good motorbike rider (good enough to be in the running during a championship race) and is also shown to know Swahili.
During third season, Frank was often the one chosen to go undercover to gain a target's trust, leading to conflict between the brothers and a crisis of conscience during the episodes "Scorpion's Sting" and "Life on the Line".
Frank was played by Parker Stevenson