Dennis Lee Tommelein was born at St. Joseph's Hospital in Ann Arbor, Michigan on Monday, September 27, 1948. He was the second child of Marie (Heiden) and Morris "Brick" Tommelein.

He graduated from Milan High School in 1966 and earned B.S. degrees from Cleary College (1970) and Madonna University (1977). Denny also received an M.S. from the University of Detroit in 1992. He served in the U.S. Army Reserves from 1970 to 1976.

On October 30, 1970, Dennis married Kathleen Mazzola in St Paul's Catholic Church in Grosse Pointe, Michigan. They had one child and were divorced in 1975.

He married Susan Watts on February 21, 1978 at St Coleman Church in Farmington Hills, Michigan. They had one daughter.

Denny worked as an Industrial Engineer with the General Motors Corporation in Pontiac while living in Plymouth, Michigan.

He died at the age of 57 on Friday, October 21, 2005 at the University of Pittsburgh Medical Center in Pittsburgh, Pennsylvania. Denny is buried at Oakwood Cemetery in Saline, Michigan.