During his convalescence in 1956, he published Profiles in Courage, a book about U.S. senators who risked their careers for their personal beliefs, for which he won the Pulitzer Prize for Biography in 1957.[93] Rumors that this work was co-written by his close adviser and speechwriter, Ted Sorensen, were confirmed in Sorensen's 2008 autobiography.[94]

Kennedy endorsing Adlai Stevenson II for the presidential nomination at the 1956 Democratic National Convention in Chicago
At the start of his first term, Kennedy focused on Massachusetts-specific issues by sponsoring bills to help the fishing, textile manufacturing, and watchmaking industries.[95] In 1954, Senator Kennedy voted in favor of the Saint Lawrence Seaway which would connect the Great Lakes to the Atlantic Ocean, despite opposition from Massachusetts politicians who argued that the project would cripple New England's shipping industry, including the Port of Boston.[96] Three years later, Kennedy chaired a special committee to select the five greatest U.S. senators in history so their portraits could decorate the Senate Reception Room.[97] That same year, Kennedy joined the Senate Labor Rackets Committee with his brother Robert (who was chief counsel) to investigate crime infiltration of labor unions.