Born April 23,1930, at the beginning of the depression to newlyweds, Max and Bessie (nee Dichter) Rothwarf, in Philadelphia, PA. He was the first of three children, born to a grocer and homemaker rapidly coming to terms with the new economic hardships affecting their community and damaging their business. He grew up in dire poverty in south Philadelphia, and later moved to Wilmington, DE for a business opportunity his father hoped would offer a new start for the family. Fred had an insatiable curiosity for learning, and he found ways to achieve the highest levels of academics available to his impoverished circumstances.  Fred, against the wishes of his parents, because of the additional transportation costs involved, attended Central High school for boys' class of 1947, which he loved. He has treasured all his memories of his classes and his lifelong friends from Central High. Unfortunately, the family move meant he completed his senior year at Wilmington's  Pierre S. Dupont high school.

He started college in Delaware, where he realized that of all the things he loved to study, science had the potential to change the world's future, and that he should focus on that area of study. Fred was able to come back to Philadelphia, by the kindness of a physics professor allowing him to become a paid teaching instructor to freshman, while only being a rising junior. Fred completed all his degrees from Temple University, BS'51, MS'53, and PhD (Solid State Physics) in1960.

In 1951, he married Rita Rhode, his high school sweetheart whom he had originally met when they were both 13. They started a family as he worked several part time jobs, seasonally at the post office and in x-ray therapy, and bioacoustics at various private hospitals and completed his doctorate in 1960. He began working for the Department of the Army doing basic research at the Frankford Arsenal after he obtained his Masters degree in Physics. Fred worked there while he was in grad school and continued to work there until 1970. In 1965, the family adventure to France began. Fred, his wife, and their three young children relocated to the suburbs of Paris, where he did postdoctoral studies in superconductivity at the University of Orsay until 1966.  The family returned to Philadelphia in 1966, where he worked at Frankford Arsenal.  In 1971, the Army relocated Fred's lab to Fort Monmouth, NJ and the family settled in Toms River, NJ. Fred worked in the fields of memory metals, superconductivity, magnetism, and metal hydrides at Fort Monmouth. While in Toms River, they made several lifelong new friendships, and his two oldest children completed high school.

By the 1980's, it was time for another family adventure. Taking a management position at the U.S. Army European Research Office in London (1980 – 1984), where Fred and family were able to live and experience London, England. At this post, Fred got to oversee research grants to laboratories located in Europe and the Middle East. After this tour of duty, he completed his years of government service working for the US Army lab in Raleigh, NC. Upon his retirement from federal service, he and Rita relocated to Reston, Virginia, where he helped found and consulted with Applied Materials Corporation of Pittsburgh.

He finished his career by teaching physics and trying to inspire a new generation to value and love science as an Adjunct Professor at George Mason University.  He taught there until he was 89, retiring in 2019.

Fred was a great father, husband, a huge fan of horrible puns, a voracious eclectic reader, and he had a lifelong passion for the sciences, languages (he had a functional knowledge of Russian, French, German, and Hebrew), good books, good food, travel, and lifelong friendships keeping in touch with friends dating back to his teens.

He is survived by his wife of 72 years Rita, and their 4 children, Marta Rothwarf (son-in-law Paul Cooper), Eric Rothwarf, Carla Fay Rothwarf, Mia Merin (son-in-law Ira Merin) and grand-daughter Lizzy Merin.

Memorial contributions in his honor can be made to the George Mason Physics Department or the American Committee for the Weizmann Institute of Science .