Rosenthal developed the bone-marrow disease osteomyelitis, causing him extreme pain and forcing him to drop out of DeWitt Clinton High School. After several operations at the Mayo Clinic, Rosenthal recovered enough to finish public schools in New York City and attend the City College of New York. At City College, Rosenthal wrote for the student newspaper, "The Campus", and in 1943, while still a student, became the campus correspondent for "The New York Times". In February 1944, he became a staff reporter there.