Rabbi Idelson was ordained at Hebrew Union College-Jewish Institute of Religion (HUC-JIR) in 1991, and has spent a majority of her career in academic settings. Following her ordination, she served as Director of Religious Activities and Chaplaincy Services at Vassar College, and from 1998-2002 as Rabbi at Carleton and Macalester Colleges. In 2002 she returned to HUC-JIR, where she served for fourteen years, including a decade as Dean of the New York campus. She launched a number of major initiatives during her tenure there, including a multi-year spirituality program that engaged faculty, staff and students in contemplative practices linked to social justice particularly focused on racial justice and environmental activism, and a new course on the art of creating meaningful worship. At an HUC-JIR Founders Day celebration in her honor in the spring of 2016, speakers cited her "profound impact" on the institution, her "zealous and principled" advocacy, and her capacity to build "a community of joy."