K-12 public school teachers faced unprecedented and novel disruptions in their workplace during the first entire school year of the COVID-19 pandemic, leading to concerns about their treatment, mental health, and job satisfaction. Between April and June 2021, 341 public U.S. K-12 school teachers from 12 states (covering Northeast, Southeast, Midwest, Southwest, West, and Pacific Northwest) completed online surveys regarding their perceived general support, experiences of ageism and sexism, job satisfaction, and mental health. Mental health symptoms mediated the relationships between sexism, ageism, and perceived support with job satisfaction (Model 1) and job satisfaction mediated the relationships between sexism, ageism, and perceived support with mental health symptoms (Model 2). Thus, the data supported two models pointing to dual co-existing pathways from (a) general support and (b) experiences of discrimination to both job satisfaction and mental health. These results highlight the importance of developing and implementing policies and programs that can improve teachers’ general support from their community along with addressing job satisfaction.