Gary obtained his B.A. degree from Mankato State University. He also served in the United States Air Force from 1966 to 1968, during which time he worked in the research division of the School of Aerospace Medicine. After serving as a public school teacher from 1968 to 1970, he went on to Luther Theological Seminary, where he obtained his M.Div. degree. A Lutheran pastor, he and his wife, Patricia, are the parents of three children.

Gary was first elected to the Minnesota Senate in 2002 Prior to that, he served in the Minnesota House of Representatives from 1997 to 2003.

Gary died of amyotrophic lateral sclerosis or Lou Gehrig's disease in 2012.