Coach Rosen is in his 7th year as an assistant coach at Tufts, and is in his 55th year of coaching baseball. He works with the corner infielders defensively and with the hitters. His coaching experience includes 20 years at the high school level, with a state championship in 1981; 11 years as a college head coach at Merrimack College and 11 years as the head coach Saint Anselm College; he was an assistant coach at Brandeis University for 3 years, working with the infielders and hitters and 1 year at Salem State University in the same capacity.

Coach Rosen served on the executive board of the Massachusetts Baseball Coaches Association for 10 years, and was named to the MBCA Hall of Fame. He is a past president of the New England Intercollegiate Baseball Coaches Association and still serves on its executive board. He was named to the NEIBA Hall of Fame in 2020.

A graduate of the University of Massachusetts at Amherst in 1972, he taught science for 35 years at Winthrop High School and Westford Academy.He is a long-time resident of Andover, Massachusetts, living near his daughter and her family.