Jilian Kossak was born and raised in New York, New York, and began dancing at age three. She formally trained at the School of American Ballet from 2009 to 2018 under the directorship of Kay Mazzo. As a young student, she performed children’s roles frequently with the New York City Ballet in productions such as The Nutcracker, A Midsummer Night’s Dream, Sleeping Beauty, Copélia, and Harlequinade. Kossak also represented the school in the President’s Bridge Dedication Ceremony in 2012, in Italian Elle magazine, and in the Glamour Woman of the Year Awards Ceremony in 2016. Kossak completed her dance education at Manhattan Youth Ballet from 2018 to 2021 under Deborah Wingert and Marina Stavitskaya. During this time, Kossak attended summer intensives at Boston Ballet, Manhattan Youth Ballet, Central Pennsylvania Youth Ballet, and Carolina Ballet. Kossak joined Carolina Ballet as an apprentice for the company’s 2021-2022 season and was promoted to the Corps de Ballet the following season.