Callen has had a relationship with the Posner Center since 2015 when she returned from her service in Senegal, West Africa as a United States Peace Corps Volunteer. During her two years in the Peace Corps she worked with teens and women on reproductive health education, WASH, small business development, and nutrition. Before joining the Posner Center team in May 2018, Callen worked as Field Manager at Grassroots Campaigns in Denver, Colorado, where she raised money for reproductive health and civil rights through face-to-face donor outreach. Callen is also a professional photographer that has shot many events at the Posner Center. She holds a B.A. in International Studies from the University of Denver and a Masters Certificate of Development Practice with Regis University.