Hughes sought election to the U.S. House of Representatives in 1938 from New Jersey's 4th congressional district, running as a strong supporter of Franklin D. Roosevelt; he was defeated by Republican D. Lane Powers by a broad margin but established a reputation as a robust campaigner.

Hughes stepped down as Assistant U.S. Attorney in June 1945, after being elected chairman of the Mercer County Democratic Party, and resumed private practice in partnership with Thorn Lord, who had been U.S.

Hughes was later appointed to be assignment judge for Union County and was thereafter elevated to the Superior Court, Appellate Division.

[3] Seeking to support his large family, however, Hughes resigned from the bench in November 1957 in resume the practice of law.

[2] Hughes was little known at the time he ran for governor of New Jersey in 1961, and was selected as the Democratic nominee only after the first choice of powerful party leaders, Attorney General Grover C. Richman, had a heart attack.

[5] Hughes proved to be a strong campaigner, however, and achieved an upset victory over Republican nominee James P. Mitchell, who had been U.S. Secretary of Labor during the Eisenhower administration, by slightly under 35,000 votes.

[2] During Hughes' campaign for re-election, the tax issue was overshadowed by a political controversy arose when Eugene Genovese, an instructor at Rutgers University, publicly stated that he would "welcome a North Vietnamese victory" in Vietnam.

Many credit the fact that then-President Lyndon B. Johnson had a very close friendship with Hughes, as one reason that Atlantic City hosted the 1964 Democratic National Convention.

[8] When Hughes was chief justice, the court issued a unanimous ruling in the Karen Ann Quinlan case, allowing an individual the right to refuse medical treatment and the right of a guardian to exercise that right if the patient cannot.

[2] Hughes left the Supreme Court in 1979 after reaching the mandatory retirement age of 70, and returned to the private practice of law.

Hughes' stepson W. Michael Murphy Jr., a former Morris County prosecutor,[11][12] placed third in the 1997 Democratic primary for governor of New Jersey.