Mr. Southwick joined the Navy shortly before the Japanese attack on Pearl Harbor on Dec. 7, 1941. He served in the Pacific, first as an aerial photographer and later aboard submarines.
His film footage and photos — some of them captured through a periscope — were used in television series, including “Victory at Sea” (1952) and “The Silent Service” (1957), and more recently on the History Channel in the series “The Color of War.”
Mr. Southwick’s photographs, long buried in a trunk, were displayed at the U.S. Navy Memorial in Washington in 1998. The Washington Post described the exhibition as “intimate and impressive evidence of one man’s war.”
After the war, Mr. Southwick became a reporter for the Associated Press and United Press wire services. His assignments included the U.S. House of Representatives and the 1956 presidential campaign.
He subsequently worked on Capitol Hill as a committee and legislative aide before moving to the White House as a special assistant to President Kennedy. Working with the White House press office, Mr. Southwick pushed for the expanded use of photography to document the president at work, his son said.
On Nov. 22, 1963, the day President Kennedy was assassinated in Dallas, Mr. Southwick conducted a press briefing in Washington and announced to reporters that Vice President Johnson had been sworn in as president.
Mr. Southwick served under Commerce Secretary John T. Connor from 1965 to 1967 as special assistant for congressional relations, then spent 20 years with the Newmyer Associates public affairs and government relations firm until his retirement.
Paul Southwick was born March 27, 1920, in Newton, Mass., and raised in Baltimore. He graduated in 1939 from what is now the private Gilman School in Baltimore and received a bachelor’s degree in economics in 1947 from Harvard University, where he led the photo desk of the Harvard Crimson newspaper.
In 1941, he and a classmate, Charles Borden, documented their cross-country summer travels in which — among other activities — they worked as farm laborers and circus performers. Borden was later killed during World War II. In 1958 Mr. Southwick helped publish the book “Harvard Interlude” with his photos and Borden’s writings.
His wife of 52 years, Susan Heider Southwick, died in 1999. Survivors include three children, Thomas P. Southwick of Princeville, Hawaii, Peter A. Southwick of Arlington, Mass., and Linda Southwick Hedio of Danvers, Mass.; and six grandchildren.