In the 1928 Seanad election six Fianna Fáil Senators were elected under the leadership of Joseph Connolly. They were immediately joined by Colonel Maurice George Moore and subsequently Dowdall found himself frequently joining with the party in divisions together with fellow independent Senator Jennie Wyse Power. He soon joined the party after their entry into the Seanad. Both he and Wyse Power stood as Fianna Fáil candidates in the 1934 Seanad election and were re-elected for nine years and served until the abolition of the Seanad.
Dowdall was also a member of the Governing Body of University College Cork. He died on 28 June 1939 and is buried in St. Finbarr's Cemetery.