Student, Brooklyn Polytechnic Institute, 1940-1943; student, Cooper Union, 1946-1950; Master of Arts (honorary), Harvard University, 1977; Doctor of Fine Arts (honorary), Lawrence University, 1987.
Hadzi served in the South Pacific, in World War II. He was a 1957 Guggenheim Fellow. He showed at the 1962 Venice biennale. Hadzi taught studio arts at Harvard University, from 1975 to 1989.
In 1990 he was elected into the National Academy of Design as an Associate member and became a full Academician in 1994.
Served with United States Army Air Force, 1942-1946. Fellow American Academy Arts and Sciences. Member American Academy Arts and Letters.
Married Cynthia Hoyle. Children: Christina, Stephen.