Hoffman began his career in aircraft engineering at Lycoming and other aerospace companies. Unusually he was the survivor of two airliner crashes, the last being in Bowling Green, Kentucky in 1943. In 1948 he was a Professor of Aerospace Engineering at Pennsylvania State University. He was offered the post of Chief of the Propulsion Section of the North American Aerophysics Laboratory (which would later became Rocketdyyne) Under his continuous leadership from 1948 Rocketdyne became the pre-eminent supplier of liquid propellant rocket engines in the United States. The initial driver for the development was the Navaho cruise missile program, which never reached production. Hoffmann took the original V-2 engine and developed it through the 42 tonne thrust engine used on the Redstone missile, to the 77 tonne thrust engines used on the Thor, Jupiter, Atlas, and Saturn I rockets, then the E-1 engine of 192 tonnes thrust, (never used on a flight vehicle), finally to the 789 tonne thrust F-1, the most powerful ever developed, that powered the Saturn V moon launcher. He capped his career with development of the reusable SSME engine for the space shuttle. Hoffmann and his wife Genevieve had four children.