Following his time at GMC, Kennedy became a 2nd lieutenant in the United States Army.
In 1966 Joe Kennedy was elected to the Senate's Fourth District, where he served for twenty-four years.
He was the Jaycees' Young Man of the Year (1962); was given the Legislative Award from the Georgia Municipal Association (1985).
The Hospital Corporation of America and the Georgia Rehabilitation Association, among many other organizations, recognized him for his hard work during his tenure as senator.
Senator Joe Kennedy was instrumental in helping to create Ogeechee Technical College.