Graduating from Jack Britt High School in Fayetteville, NC, Sammy first found rugby while attending the Army West Point, one of the premier collegiate rugby programs. Sullivan first saw rugby at Athletic Day, during basic training at West Point and thought she would give it a try, following the footstep of her father who also played in college and in the Army. Rising high through the rugby ranks, Sullivan was named the 2019 Prusmack Award winner, recognizing the top collegiate sevens athlete in the nation.
As part of the World Class Athlete Program, an initiative promoting graduating service members through sports careers, Sullivan follow graduation by entering the Women's Premier League, sparking an impressive start to her fifteens career that resulted in a roster invite to the 2022 Pacific Four Series with the USA Women's Eagles, debuting against Canada in June of that year.
Sullivan's sped and agility is undeniable, a skill set that also caught the eye of the USA Women's Sevens, drawing her back to the sevens pitch and USA residency in the later half of 2022. Sullivan would make her USA Sevens National Team debut during the Rugby World Cup Sevens in Cape Town, before making her World Rugby Sevens Series debut in Dubai that December. Becoming one of only a few Eagle to debut in both disciplines in the same year.