In Rosengarten's first two seasons in 2020 and 2021 he played in a combined five games with no starts. In the 2022 season, Rosengarten played in and started all 13 games for the Huskies at right tackle. For his performance on the 2022 season, Rosengarten was named First TeamFreshman All-American. During the 2023 season, Rosengarten was a part of the Huskies' Joe Moore Award-winning offensive line, which is awarded to the nation's best offensive line. After the conclusion of the 2023 season, Rosengarten decided to declare for the 2024 NFL draft.