He worked there in the textile industry and then in the Town Hall, which made the start for his rise in state politics.

He was elected to the Connecticut House of Representatives in 1949, but managed to divide his time between state and local affairs.

When Ribicoff resigned as Governor of Connecticut to become a member of President John F. Kennedy's Cabinet, Dempsey succeeded him, becoming the first person to hold this position since the early colonial period who had been born in Europe.

[1] In 1969, leaders of both parties introduced the Legislative Management Act to establish support staff and control the operating budget of the Assembly.

[2] After leaving office, Dempsey became the President of the Indian Trails Council of the Boy Scouts of America.