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.