Leo Francis Dooley is the 17 year-old bionic teen who is Adam, Bree, and Chase's step-brother and their closest friend. He is one of the five main characters and is the team's Strategic Mission Specialist. He is considered a social outcast in most circumstances considering his small amount of friends. Donald had a lack of trust for Leo due to Leo's tendency to accidentally destroy things, but has started to change his opinion, as he made Leo the team's "Mission Specialist." He gained a bionic arm in You Posted What?!?, after his right arm got extremely injured by Taylor. He gains a bionic leg in Space Elevator, when the elevator crushes his left leg severely. Leo in 2019, appears in Back From the Future.
He is portrayed by Tyrel Jackson Williams.