Laurie Hernandez is an award-winning gymnast, writer, and co-host on Season 1 of American Ninja Warrior Junior! She competed as a member of the "Final Five" gymnastics team at the 2016 Summer Olympics, where she won a gold and silver medal. She has also competed on ABC's Dancing with the Stars and is a New York Times bestselling author.

Matt Iseman is a co-host on American Ninja Warrior Junior! He also hosts NBC's American Ninja Warrior and has appeared on The New Celebrity Apprentice, Live Rescue, and other shows. Outside of Ninja Warrior, he is a stand-up comedian and has performed on Comics Unleashed.