Leo is a 7 year old American boy, leader of the Little Einsteins, and the one who pilots Rocket. He is also Annie's big brother, for which they share a very good brother-sister relationship as seen in Brothers and Sisters to the Rescue. His main talent is conducting with his most precious object, his baton: which he never goes anywhere without as mentioned in I Love to Conduct. Whenever he hugs Annie, he puts one arm around her shoulder. His many skills with his baton also includes the ability to conduct cows, as seen in The Christmas Wish. He also worries about Annie whenever they go on missions and makes sure she doesn't get hurt. He owns a musical pet named Melody, which he adopts in episode Melody the Music Pet. Doing so, he uses his baton, and Melody enjoys it gladly. In A Galactic Goodnight, he uses his baton as a nightlight at bedtime.