Susan graduated magna cum laud with a Bachelor of Arts in Letters from the University of Oklahoma in 1983. At the University of California-Berkeley, she earned a Masters in History in 1985 and Ph.D. in United States History in 1992. She earned a Certificate in Archival Science from the California State Library in 1994, and later

held a Ford Foundation/Social Science Research Council Sexuality Research Postdoctoral Fellowship in the History Department at Stanford University, 1998-2000.

From the late 1980s through the early 2000s, Susan worked primarily as an independent scholar and filmmaker, and at times as adjunct faculty at various San Francisco Bay Area colleges and universities, including Ohlone Community College, Mills College, University of San Francisco, San Francisco State University, and University of California-Berkeley. She had a day job for several years as Executive Director of the GLBT Historical Society in San Francisco, before accepting a scholar-in-residence appointment in the Department of Critical and Cultural Studies at Macquarie University in Sydney in 2003, where she helped establish the Somatechnics Research Network. Susan became a fulltime academic starting in 2007, with distinguished visiting faculty positions at Simon Fraser University in Vancouver, University of California-Santa Cruz, Harvard University, Yale University, Northwestern University, Johns Hopkins University, and Mills College. She has held two tenured professorships, first as Associate Professor of Gender Studies at Indiana University, then as Associate Professor of Gender, Women’s and Sexuality Studies at the University of Arizona. At UA, Susan directed the Institute for LGBT Studies and launched a Transgender Studies Initiative that included a faculty cluster hire and the establishment of TSQ: Transgender Studies Quarterly, which she co-founded and co-edited for a decade. She earned the rank of Full Professor at UA before retiring from that institution and becoming Professor Emerita in 2019. In 2022-23, she was Marta Sutton Weeks Senior Faculty Fellow at the Stanford Humanities Center.

She is the recipient of two lifetime achievement awards for contributions to the LGBT Studies, the Kessler Award from CUNY Graduate Division, and the Brudner Prize from Yale University.