After high school, he worked for a year at a nearby zipper factory of the G. E. Prentice Company to earn additional funds for college.

Generally liberal in his outlook, he surprised many by opposing a $32 million appropriation for the construction of a dam in Enfield, Connecticut, arguing that the money was better spent on military needs and foreign policy initiatives such as the Marshall Plan.

In 1952, he made an unsuccessful bid for election to fill a vacancy in the United States Senate, losing to Prescott Bush.

After returning to his legal practice for two years, he ran for governor against incumbent Republican John Davis Lodge, winning the election with 49.5% and by just over three thousand votes.

[1] As governor (1955–1961), Ribicoff soon faced the challenge of rebuilding his state in the wake of devastating floods that occurred in the late summer and fall of 1955, and he successfully led bipartisan efforts to aid damaged areas.

He reportedly declined the position of attorney general for fear that he might create needless controversy within the emerging Civil Rights Movement because he was Jewish, and he instead chose to be secretary of health, education, and welfare (HEW).

[2] He was finally elected to the United States Senate in 1962, replacing retiring incumbent Prescott Bush by defeating Republican nominee Horace Seely-Brown with 51% of the vote.

Ribicoff supported Johnson at first but eventually turned against the Vietnam War and the president's management of it, believing that it drained badly needed resources away from domestic programs.

Ribicoff spent the remaining years of his Senate career fighting for such issues as school integration, welfare and tax reform, and consumer protection.

In 1978, Ribicoff's niece Gail Rubin was shot and killed in the Coastal Road massacre in Israel by Palestinian terrorists.

President Jimmy Carter released a statement crediting Ribicoff with having "compiled a distinguished career of public service that can serve as a model of decency, compassion, and ability.

"[7] In 1981, Ribicoff fulfilled his pledge to retire from the Senate and took a position as special counsel in the New York law firm of Kaye Scholer LLP and divided his time between homes in Cornwall Bridge, Connecticut, and Manhattan.