Pappas began her career as a public school pre-k teacher in a Newark, New Jersey. She wrote about her experience in the book Good Morning, Children (Gryphon House, 2009). She then developed a pipeline of early childhood teachers and leaders by spearheading Teach For America's national Early Childhood Education initiative. In 2011 she began running the NYC Department of Education’s Early Childhood Education Division. Currently, as CEO of the Division, Pappas oversees teams responsible for ensuring Pre-K for All programs across the city offer high quality classroom instruction and family engagement that lays the foundation for future success. In 2016, Pappas was awarded the Peter Jennings Award for Civic Leadership by Teach for America.