Born in Oshkosh, Wisconsin, Stadtmueller received a Bachelor of Arts degree from Marquette University in 1964 and a Juris Doctor from Marquette University Law School in 1967. He was in private practice in Milwaukee from 1968 to 1969. He was an Assistant United States Attorney of the Eastern District of Wisconsin from 1969 to 1974, and then first assistant for that district from 1974 to 1975. He returned to private practice from 1975 to 1976, but was again an Assistant United States Attorney from 1977 to 1978, then the Deputy United States Attorney from 1978 to 1981, finally becoming the United States Attorney for the Eastern District of Wisconsin from 1981 to 1987.
