During World War II, embedded with the United States Marine Corps, he covered the battles at Attu (with the U.S. Army), Tarawa, Saipan, Iwo Jima, and Okinawa.

He had two sons, John and Robert L. Jr. After Sherrod's college graduation, he worked for newspapers in the South until 1935, when he joined Time, Inc.

Sherrod was one of only a few who were at Tarawa that the President knew personally and could trust to advise him on this matter from the point of view of the Marines on the ground.

Unfortunately, Sherrod also admitted to being responsible for spreading the rumor that Joe Rosenthal's famous photograph of the Marines' second flag raising on Mount Suribachi was "staged"; he later confessed that he was wrong and apologized.

In 1944 he was also responsible for repeating and amplifying the spurious charges of Marine General Holland Smith that the Army performed poorly during the invasion of Saipan, claiming in a September 1944 Time magazine article that a regiment of the 27th division "froze in their foxholes" during the Gyokusai attack of 6-7 July, reigniting the controversy and further damaging Marine/Army relations.