He was the grandson of Chief Justice of the United States Charles Evans Hughes, the 1916 Republican Party nominee for President, and claimed in his memoirs to have been used as a "campaign baby" as an infant.
[2] This was interrupted in early 1929, when Hughes's father was appointed United States Solicitor General by the new President, Herbert Hoover.
The family's stay in Washington, D.C., was relatively brief; Charles Hughes Jr. was compelled to resign as Solicitor General when his father was appointed Chief Justice of the United States upon the death of William Howard Taft in 1930.
Hughes then attended graduate school at Harvard University, where he wrote his thesis, The Crisis of the Imperial French Economy, 1810–1812.
During the war, he served as an intelligence analyst whose work was generally well received, despite his association with political views that were, especially in the context of the United States military establishment of the time, decidedly left wing.
Hughes, by then a lieutenant colonel, was honorably discharged from active duty in 1946 and was soon reassigned as a civilian intelligence analyst, returning to Europe.
In 1962, Hughes filed as an independent candidate for the final two years of the unexpired US Senate term of President John F. Kennedy.
The major-party candidates were the Democratic Party members Edward M. Kennedy (the President's youngest brother) and Eddie McCormack (a nephew of the Speaker of the House) and the Republican George C. Lodge.
Hughes collected well over the 72,000 signatures then required under Massachusetts law for placement on the ballot as an independent candidate; the September Democratic primary eliminated McCormack from further contention.
In the fall of 1963, Hughes agreed to become co-chairman of the SANE organization, alongside renowned pediatrician and fellow activist Benjamin Spock.
He also found himself in an increasingly isolated position on the Harvard faculty, opposed to both the Vietnam War and also many of the actions that began to be taken in opposition to it.