|1963–66||Bishop McDevitt High School (HC)|
|1967–68||Villanova University (Part-time assistant)|
|1969–75||Villanova University (Offensive line coach)|
|1976||Idaho State University (Assistant coach)|
|1977–78||Saskatchewan Roughriders (Offensive line coach)|
|1978||Saskatchewan Roughriders (HC)|
|1980–81||Calgary Stampeders (Assistant Coach)|
Posadowski played at Villanova University from 1957-1959.
Posadowski's coaching career began at Bishop McDevitt High School, where he compiled a 17-15-5 in four season as head football coach. He spent two seasons as a part-time assistant at Villanova before becoming the Wildcats offensive line coach in 1969. Posadowski spent one season (1976) as an assistant at Idaho State University.
Posadowski joined the Saskatchewan Roughriders in 1977 as offensive line coach. After a 0-5 start to the 1978 season, head coach Jim Eddy was fired and Posadowski was named head coach. The Roughriders finished the season 4-11-1 and Posadowski was replaced by retiring quarterback Ron Lancaster.
Following Lancaster's hiring, Posadowski was moved from the head coaching position to director of scouting and recruiting. Posadowski's final coaching position was as an assistant with the Calgary Stampeders.
- "Full-Time Assistant". The Dispatch. March 19, 1969. Retrieved 2010-08-11.
- "Roughies replace Jim Eddy". The Montreal Gazette. August 17, 1978. Retrieved 2010-08-11.
- "Lancaster Now Coach". The Spokesman-Review. November 1, 1978. Retrieved 2010-08-11.
- "Gotta promises changes to Stamps". Ottawa Citizen. November 4, 1981. Retrieved 2010-08-11.