He has been an umpire in the St. Louis area for over 35 years. Radermacher was a member of the Greater St. Louis Association of Umpires from 1983 to 1988. He was with the Midwest Umpires Association from 1989 to 2000. He has been an independent umpire for the past 18 years. Radermacher is a fixture at many high school, American Legion, and Metro Collegiate games in the St. Louis area. He was on the Missouri Valley Conference umpire staff and worked NCAA Division One games for St. Louis University. In 1994, he umpired the Missouri Valley championship tournament. In 1995, he umpired the Conference USA championship tournament. He was on the Big 8 Conference umpire staff. He umpired NCAA Division II games for SIU-Edwardsville, and NCAA Division Three games for Washington University. Radermacher umpired in the NAIA Conference for Missouri Baptist College, McKendree College, Greenville College, Principia, and MacMurray. He worked junior college games for Jefferson College, Florissant Valley, Forest Park, Mineral Area, and St. Charles. He also umpired junior college district tournaments and super regional tournaments. In 1991, he was an umpire at the Missouri High School State tournament. He has umpired many high school games, including district, sectional, and quarterfinal games. He was an American Legion umpire in District 9 and District 10. He also worked American Legion State tournaments and zone tournaments. He has umpired many games in the St. Louis Metro Collegiate League, including playoff and championship games. He was an umpire in the CYC Senior Men’s League. He umpired games during the United States Olympic Festival at Busch Stadium. Radermacher graduated from St. Louis University High School in 1975, and then attended St. Louis University. After graduating from St. Louis University, he attended Southwest Missouri State University for three years.