Bowen began his political career in 1977 as a member of Llantrisant Community Council. He was first elected to Cardiff Council in 1995, as the Council's only representative for the Welsh nationalist party, Plaid Cymru. He represented the Creigiau & St Fagans ward.
Bowen later became the Council's executive member for traffic and transportation but, in May 2011, relinquished this position to become Lord Mayor of Cardiff. He was the first ever Plaid Cymru mayor of the city.
In November 2011 Bowen announced he would not be standing for re-election to the Council in May 2012. He claimed to be proud of his contribution, while the Council's transport chief, to the introduction of the sustainable travel city programme, park-and-ride facilities and the pedestrianisation of some of Cardiff's main city streets. The 2012 local government elections saw Plaid Cymru lose the Creigiau & St Fagans seat to the Conservatives.
Bowen was a lecturer in zoology and later professor of cell biology at Cardiff University until his retirement in 2010. He is the author of several books and research papers. On his retirement he was given the title of emeritus professor.
- Peter Law Veteran councillor to ‘go out with a bang’ after 35 years of service, Western Mail, 15 November 2011. Retrieved 2011-12-20.
- Delme Bowen becomes first Plaid lord mayor of Cardiff, BBC News, 19 May 2011. Retrieved 2011-12-19.
- City transport chief new Lord Mayor and council executive sees reshuffle, GuardianCardiff, 20 May 2011. Retrieved 2011-12-20.
- "Cardiff council elections: The story in each ward". Your Cardiff (WalesOnline). 3 May 2012. Retrieved 2012-05-05.
- Cardiff today – Lord Mayor, market pickle and basement masterclass, GuardianCardiff, 19 May 2011. Retrieved 2011-12-20.
- Biographical Note on the Lord Mayor: Councillor Professor Delme Bowen, Cardiff Council website, updated 23 May 2011. Retrieved 2011-12-20.