Before entering Parliament he was Public Relations Officer for the Labour Party in Wales 1968. Together with Emrys Jones, Regional Organiser for the Wales Labour Party, and Gwyn Morgan, Assistant General Secretary to the UK Party, he drafted Labour's evidence to the Crowther/Kilbrandon Royal Commission on the Constitution.
In 1970, at the age of 27, he was elected Member of Parliament (MP) for Carmarthen, defeating the president of Plaid Cymru, Gwynfor Evans, with a majority of 3,600 votes. He held on to the seat by just 3 votes (with five recounts) in the February 1974 general election, but lost the seat back to Evans by 3,640 votes in the October election of that year. When MP he was in 1974 Parliamentary Secretary to Rt Hon Roy Jenkins, the Home Secretary, and was also a member of the Council of Europe. Throughout his time in Parliament he campaigned for more devolution for Wales, an issue that split the Welsh Labour Party deeply.
In June 1974, in a letter to the Executive of the Carmarthen Constituency Labour Party, he warned of the dangers of the ever leftward drift of the party saying – I cannot any longer conceal my acute concern about some developments in the Labour Party which will in my view not enhance the prospects of the Labour Party and will also affect the longer term unity of the Labour Movement. I happen to believe strongly in the principles of Social Democracy. When in 1975, Prime Minister Harold Wilson held a referendum on Britain’s membership of the European Economic Community (EEC), Gwynoro was the Campaign Organiser in mid/west Wales for a ‘Yes’ vote.
During the period Roy Jenkins was in Brussels as President of the European Commission the two communicated on a very regular basis as how a new third force in British politics could be established.
In 1981 he helped establish the Social Democratic Party. Together with Tom Ellis, former MP for Wrexham, and others, he created a powerful Welsh voice within the UK SDP. Gwynoro Jones stood in the Gower by-election of 1982 when Labour's 19,000 majority was reduced to 7,000. He was Chair of the SDP in Wales for two three-year periods before the merger of the SDP with the Liberals. During the days of the SDP-Liberal Alliance he chaired its National Committee in Wales from 1983 to 1989. In the 1980s Gwynoro became a powerful advocate for constitutional and electoral reform, and was a renowned orator at conferences and public meetings across the UK. A strong advocate of the alliance with the Liberals, he was often at loggerheads with David Owen. At the merger debate in Sheffield during February 1988, Gwynoro referring to Owen’s refusal to join the SDP in a merged party with the Liberals was famously reported as telling delegates - you can’t change British politics on the basis of hero worship. 
When the Liberal Democrat Party was formed he stood for the Presidency and received over 10,000 votes. He topped the poll in the vote for the party's National Committee and became vice chair of the Policy Committee. In 1992 he stood for the Hereford seat and received over 23,000 votes.
After that Gwynoro concentrated on his business activities, and from 1993 until 2012 was head of EPPC-Severn Crossing Ltd, a school inspection and conferencing business. During that period the company inspected over 10,000 educational establishments in England and Wales. Gwynoro visited some 1000 of Wales’s schools on inspections and regularly expressed concerns about standards in teaching, learning and performance. In August 2012 it was reported that EPPC-Severn Crossing had debts of £180,000 in the autumn of 2011 and some sub-contracted inspectors had not been paid for inspections they had done. During the following year these matters were resolved. When the contractual arrangements for the administration of school inspections were changed by the Welsh Government and Estyn from September 2012 the company ceased trading. In addition to being a Lay Inspector of schools he was also an Investors in People Adviser/Assessor, External Assessor Performance Management of Headteachers, External Assessor for EFQM European Business Excellence Model, Consultant/Assessor Law Society Lexcel Standard and Health Inspectorate Wales lay inspector.
He was very supportive of the Rainbow Alliance proposals which aimed to form a joint administration in Cardiff between Plaid Cymru, Liberal Democrats and Conservatives in 2007 - being particularly disappointed at the eventual formation of a Labour/Plaid coalition for Assembly term 2007 -11. He rejoined the Liberal Democrats in 2011, citing Nick Clegg's courage in entering a coalition in Westminster, but was also known to have said at the time - I understand why it is happening but no good will come of it. He soon became a critic of the way the coalition was operating and the damage it was doing to the party’s electoral prospects.
Following the UK General Election of May 2015, Gwynoro became active in politics again expressing his determination to do what he could to rebuild the party that he had actively helped to develop in the 1980s. He is an active blogger  and has his own YouTube channel. He was particularly saddened by the passing of Charles Kennedy and has been critical of Plaid Cymru's performance in the Welsh Assembly.
Gwynoro is a passionate European and is the Vice Chair of the Wales Council of the European Movement. Constitutional and Electoral Reform are other campaigns he actively supports and he is a member of the Electoral Reform Society.
- "SDP Sketch: The bitter end of a new beginning | 1980-1989 | Guardian Century". The Guardian. Retrieved 2017-04-07.
- "UK General Election results: April 1992 [Archive]". Politicsresources.net. 1992-04-09. Retrieved 2017-04-07.
- "Call for school changes in Wales as GCSE data published". BBC News. 2011-05-23. Retrieved 2017-04-07.
- "School inspectors 'owed thousands' by EPPC Severn Crossing". BBC News. 2012-03-10. Retrieved 2017-04-07.
- "Labour: Plaid couldn't run a cockle stall". Wales Online. 2013-03-30. Retrieved 2017-04-07.
- "Betsan's Blog: Brand detoxification". BBC. 2011-03-05. Retrieved 2017-04-07.
- "Welsh Lib Dems hope for new start as conference begins". ITV News. 2015-09-19. Retrieved 2017-04-07.
- "Liberal Democrat Voice Stars of 2015 Part 1". Libdemvoice.org. 2015-12-29. Retrieved 2017-04-07.
- "Gwynoro Jones". Gwynorojones.blogspot.co.uk. Retrieved 2017-04-07.
- "Gwynoro Jones". YouTube. Retrieved 2017-04-07.
- "A former Labour MP who was a leading Welsh figure in the SDP remembers the young Charles Kennedy". Wales Online. 2015-06-03. Retrieved 2017-04-07.
- "Door to anti-Labour Welsh Assembly coalition should be kept open, says former Labour MP". Wales Online. 2015-06-28. Retrieved 2017-04-07.
- "'Plaid Cymru is now more socialist than nationalist and has become Labour's helper' argues former Labour MP". Wales Online. 2015-10-23. Retrieved 2017-04-07.
- "Politician is keeping up the family tradition", icWales.co.uk, 14 December 2006
- "Election results for Merthyr Tydfil and Rhymney, 3 May 2007". National Assembly for Wales. 2007-05-03. Retrieved 2017-04-07.
- Times Guide to the House of Commons October 1974
- Leigh Rayment's Historical List of MPs [self-published source][better source needed]
- Hansard 1803–2005: contributions in Parliament by Gwynoro Jones
|Parliament of the United Kingdom|
|Member of Parliament for Carmarthen
1970 – October 1974