Moselle grew up in Wisconsin and attended University of Wisconsin-Superior (UWS) starting in 1946 after serving two years in the U.S. Army during World War II.

Moselle was born in Gile, Wisconsin and attended Hurley High School, where he played basketball, baseball and football.

[1] When the war ended, he enrolled at the University of Wisconsin-Superior, then known as Superior State Teachers College, where he studied health and physical education.

[1] In the Browns, Moselle joined a team transitioning into the NFL after four years and four championship victories in the All-America Football Conference.

[4] Led by quarterback Otto Graham, fullback Marion Motley and ends Dante Lavelli and Mac Speedie, the Browns finished the season with a 10–2 win–loss record and won the NFL championship over the Los Angeles Rams.

[3][7] Brown traded Moselle to the Green Bay Packers in 1951 along with linebacker Walt Michaels and several other players in exchange for the rights to tackle Bob Gain.

[8] Moselle played the following two seasons for Green Bay, but the team finished no better than fourth place in the NFL's National division.