Though Freudenberger had many jobs during his life, including practitioner, editor, theoretician, and author, his most significant contribution is in the understanding and treatment of stress, chronic fatigue and substance abuse.
[4] After the beating of Freudenberger's grandmother and the death of his grandfather, he fled to the United States, with his parents' approval and a false passport.
Traveling alone through multiple cities and countries, Freudenberger arrived in New York, where he cared for himself until a relative gave him shelter.
Once he had settled in New York, Freudenberger quickly learned English, and graduated from a junior high school with honors.
When his parents finally came to the US, Freudenberger began work as a tool and die maker's apprentice to assist them, instead of beginning high school.
[3] Without a high school diploma and working at the manufacturing plant, Freudenberger began attending night classes at Brooklyn College.
During this time, Freudenberger was also a student at the National Psychological Association for Psychoanalysis (NPAP) (as well as NYU) and continued to work in a factory at night.
[3] During the 1970s, Freudenberger decided to help the development of the free clinic movement, which, unusually for the time, treated substance abusers.
Late in life he was interviewed by video by the Shoah Foundation for its collection of memoirs of Jewish Holocaust survivors.