Among his officiating highlights, Leitner worked more IHSA basketball and football tournament games than any official in the state's history, earning 27 consecutive boys basketball regional assignments. He also worked the IHSA boys basketball state finals in 1973, 1974 and 1976, including the 1976 championship game, and three IHSA football finals, including the first-ever 2A state championship game in 1974. A charter member of the Gateway Conference officiating crew in 1988, Leitner was part of the crew that officiated the 1990 and 1993 NCAA Division I-AA quarterfinals and he served as an associate official for the Big Ten Conference from 1984-88.
Leitner also was called upon to officiate two IESA state championship games, the 1990 National Catholic Basketball finals, three Shriner All-Star football games and the 1980 IBCA All-Star Classic, while also working for two seasons in the Midwest Professional Football League.
Leitner is a member of the Illinois Basketball Coaches Association, Peoria Officials and Bloomington/Normal Officials Halls of Fame.
After a successful early career coaching elementary school athletics in the Champaign-Urbana area, Merv entered the Peoria athletic scene in 1962 as football coach at Spalding High School. His first three teams had a combined 24-2-1 record. His 1965 squad went 9-0-1, and in 1967 he was 10-0 followed by an 8-1 year in 1968. His last five Irish teams, 1972-1976, went 35-11-3.