Dan graduated from the U.S. Naval Academy in 2002, and served as a U.S. Navy SEAL officer from 2003 to 2015. He was severely injured in Afghanistan in 2009, resulting in the amputation of both legs above the knee. Since then, he has competed in para-nordic skiing in the 2014 and 2018 Paralympic Winter Games — he won one gold medal, four silver medals, and one bronze medal in 2018 alone. He recently graduated from Harvard Kennedy School and Harvard Divinity School with masters degrees in public administration and theological studies.