Len Froyen was born July 1, 1934, in Freeport, Illinois. Upon his high school graduation, Froyen attended Iowa State Teachers College (later the University of Northern Iowa). He was active in a variety of activities and was elected president of a few different organizations, including the Student League Board, Sigma Tau Gamma fraternity, and the regional Association of Residence Halls. While at ISTC, Froyen lived in Stadium Hall, located underneath Latham Stadium, and also worked as a resident assistant. Froyen graduated from ISTC in 1957. He married fellow ISTC graduate Gail Froyen, who later worked as a Price Lab School librarian.

Froyen then attended Michigan State University, graduating in 1958 with a master's degree in Guidance and Counseling Psychology. From 1958-1960, he served as an Instructor in Teaching at the Price Lab School, where he taught social studies. He then worked as the Director of Guidance in Independence in Independence Public Schools from 1960-1963 before joining the ISTC College of Education faculty in 1963. With the exception of a one year absence during which he completed his Ed.D. at Indiana University (1970), Froyen remained at UNI for the remainder of his career, which included a period serving as head of the Department of Educational Psychology and Foundations. Research topics he pursued included classroom management and Iowa Schools and "current concerns in school disciplines."

Froyen retired from UNI in 1994 but remained connected to campus, serving as a deacon at St. Stephen the Witness Catholic Student Center. Additionally, he worked on the inaugural teacher education convocation, coordinated the Stadium Hall reunion, and led the campaign to renovate the Lang Hall / Old Aud. He received the Alumni Service Award in 2009.