He graduated second in his class from the U.S. Naval Academy in 1974 with a Bachelor of Science Degree in American Political Systems. He retired from the Navy as a Rear Admiral in 2005.
He earned a master's degree in public affairs and a PhD in political economy from Harvard University in 1984.
In the summer of 2005, his 3-year-old daughter Alex was diagnosed with glioblastoma, an aggressive form of brain cancer. His daughter's cancer has since gone into remission.
He is the son of Kathleen L. (Schlichte) and Joseph Sestak. His father was a Slovak emigrant, from the village Dolne Lovcice. His mother is of half German and half Irish descent.