Stephanie Jallen was born with CHILD syndrome, Congenital Hemidysplasia with Ichthyosis and Limb Defects Syndrome. This meant that Jallen's left leg had to be amputated, her left side is under-developed, and she suffers from rashes.
Her nickname, Hopper, comes from the fact that when her prosthetic limbs weren't being worn, she had to hop. Jallen has always been active and learned to play soccer with her friends. She does have a crutch but she uses it mainly for balance and is happy to stand or move around on her leg. In an interview she said that she would not want to have her limbs back to normal as that would just make her "boring".
At her debut Paralympics, the 2014 Winter Paralympics in Sochi, Jallen competed for Team USA in three events: the Super-G, the slalom, and the super combined (Jallen is competing in standing in all events). She was the second-youngest member of the national team. She came third in the Super-G, finishing 5.94 seconds behind Marie Bochet; also finishing behind Solène Jambaque, both of France. Jallen came third in the super combined with a time of 1:25.15 seconds, 4.74 seconds behind Bochet, who won.