In response to the shortage of qualified secondary mathematics and science teachers in the United States, alternative certification programs (ACPs) are proliferating. This study used identity as a theoretical lens to examine the incoming identities of 19 participants with post-baccalaureate degrees who entered an ACP. Within this cohort, the participants' incoming teacher identities ranged from "Always a Teacher" to "Late Deciders" to "Career Explorers." Participants held multiple non-teaching identities, some which supported their teacher identities (e.g., parent, tutor) while other identities (e.g., college instructor) created tension. Implications include recommendations for alternative certification program development and further research. (Contains 1 table, 1 figure and 1 endnote.)