Rusak made her junior international debut at the 2021 Ritam Cup, finishing seventh in the all-around.[2] At the Irina Deleanu Tournament, she took 13th place.[3] At the 2021 Junior Pan American Championships, she won a gold medal with the American team.[4]
In 2023, she won a silver medals in the team and ball events at the Gymnastik International in Schmiden.[5][6] She won the hoop title at the 2023 Rhythmic Challenge, where she also finished fourth in the all-around.[7] In March, she took 10th place in the all-around at the Aphrodite Cup in Athens. Then in the event finals, she won bronze with clubs and silver with ribbon.[8][9] In May, she won gold in the all-around and with ball and ribbon, silver with clubs and bronze with hoop at the Ritam Cup.[10] At the Pan American Championships in Guadalajara, she won a gold medal in the team event alongside Rin Keys and Megan Chu.[11] She then won a silver medal in the hoop final, behind Keys.[12][13]
Rusak became age-eligible for senior competitions in 2024. At the 2024 Rhythmic Challenge, she finished 13th in the all-around, and her best apparatus result was ball, where she finished fourth.[14] At the 2024 USA Gymnastics Championships, she finished seventh in the all-around.[15] As a result, she was added to the senior U.S. national team.[16] She finished 13th in the all-around at the 2025 Rhythmic Challenge.[17] She won the all-around competition among athletes born in 2008 at the 2025 USA Gymnastics Championships.[18]