Otto Osworth is a young orphan from the year 2001 and one of the main characters of Time Squad. He used to live in an orphanage run by the cruel Sister Thornly, who punished him for reading. He was adopted by Officer Buck Tuddrussel and the Larry 3000 when they miscalculated on a mission to find Eli Whitney and became an unofficial member of the team.
Otto is a young boy that is quite short in stature. He has red hair, freckles, and dark green eyes. He typically wears a blue t-shirt, black shorts, red sneakers, and thick circular-framed glasses.
Outgoing, obsessed with history, and well-spoken, Otto serves as both the moral compass and the problem-solver of Time Squad. Otto often finds himself to be the only one capable of handling the missions the team is given compared to his somewhat incompetent partners. He is kindhearted and intelligent as well.
However, Otto is still a child. He likes to play with toys, color, and roughhouse. He easily goes along with Tuddrussel's immature antics and can sometimes lend himself to trickery and pranks. He gets easily excited about historical figures, especially those in the times of the American Revolution like George Washington. Otto often attempts to emulate his newfound family, adopting their mannerisms and skills.
Otto has an enormous knowledge of history in nearly every field, making him very valuable to his team. He is also well-versed on literature and loves to read. Living in the orphanage gave Otto a need for self-defense, so he is skilled at self-taught karate. Otto also has a natural talent for shooting guns.
- Otto's appearance is based on that of Sherman from "Mr. Peabody and Sherman".
- It is never explained why Otto is an orphan. Series writer Carlos Ramos stated that the writers most likely didn't put much thought into it, but would have elaborated more on his past had the series been renewed for more seasons.
- Otto's short size remains with him his whole life. He is at almost the same height when he is an elderly man, as seen in Old Timer's Squad.
- Otto was seven years old when he was adopted by the Time Squad. He turns eight in Love At First Flight.
- Otto initially shares a room with Tuddrussel, as seen in Dishonest Abe. However, he eventually gets a room of his own, as seen in Floundering Fathers.
- Despite being the most competent of the group, he sometimes causes historical inaccuracies to happen when fixing the ones that have already started. For example, he solves the problem of Josephine Bonaparte preventing her husband's conquests across Europe by convincing her that her place in life is fighting alongside her husband, only to realize a second too late that the battle he convinced Josephine to fight in is the Battle of Waterloo. It's implied that the French still lost the battle of Waterloo, but it isn't made clear and Otto is concerned that he might have tipped the odds in their favor. In a much later episode, Otto's passionate drive to save the mission and to get back at Louis Pasteur's obnoxiously rude behavior towards him leads him to give the idea for Marie Curie to invent the popsicle, which wasn't supposed to be invented for about forty years by Frank Epperson.
- Although Otto is one of the main characters of Time Squad, he doesn't appear alongside Buck and Larry on Cartoon Network's 20th Anniversary commemorative poster.