Steve was an umpire for 39 years, working games in St. Louis and throughout the country. He umpired college baseball for 35 years in the NCAA, ACC, SEC, NAIA, MVC, Summit League, Big Eight, and Big 12. He worked 65 conference tournaments, 41 conference championship games and 40 regional championship games. He also officiated numerous junior college tournaments.

Dunahue umpired professional baseball in the Frontier League for 19 years. The Frontier League has 10 teams, including the River City Rascals and Gateway Grizzlies. He officiated three Frontier League all-star games, five divisional series, and three championship series.

A hard-throwing right-hander, Dunahue pitched for the C&H Travelers in the late 1970s and early 1980s. He was on the Travelers team that won the 1980 Metro-Collegiate League championship. In the late 1980s, he became of the Travelers coaches.

From 1976-78, he pitched for Ritenour High School and also Thoman-Boothe American Legion Post 338. He was a pitcher for Florissant Valley Community College from 1978-80. Dunahue coached amateur baseball for nine years. He worked as an instructor at Balls-N-Strikes for 12 years.