He was re-elected for Cork West at the next five general elections, until he retired from the Dáil at the 1954 general election.
He was then stood in the 1954 elections to Seanad Éireann, on the Agricultural Panel, and was elected to the 8th Seanad. He was re-elected by the Agricultural Panel at the next three Seanad elections, before retiring from politics in 1969, after completing his term in the 11th Seanad.
Ted O'Sullivan died in 1971.
His niece Peggy Farrell was a senator from 1969 to 1973.