Hassid was born on October 1, 1899, in Jaffa, Palestine. He emigrated to the United States in 1920. Hassid received A.B, M.S. and Ph.D. degrees from University of California, Berkeley in 1925, 1930 and 1934, respectively. Hassid spent all of his academic career at the University of California, Berkeley, and became research assistant of Dennis Robert Hoagland in 1927. He was appointed professor of plant nutrition in 1947, and professor of biochemistry in 1950. He retired in 1965 and until his death in 1974 he was professor emeritus.