He then did his residency in Orthopedic Surgery in Buffalo General and Children's Hospital in New York state from 1948 to 1953.
In 1955, he became an Assistant Professor of Orthopedic Surgery at Yale School of Medicine.
During his time at the Henry Ford Hospital, Frost made many breakthroughs, which changed the paradigm of bone biology.
Frost moved to Pueblo, Colorado in 1973 — drawn by the mountains, climate, and lifestyle — bringing with him his international reputation as a dogged researcher, talented orthopaedist and prolific author.
While there he continued his active participation at the Sun Valley Workshops where he interacted with participants to develop cancellous bone histomorphomety (1977), generate and refine the mechanostat hypothesis (1987), and the ever-evolving Utah Paradigm of Bone Physiology (1997).