She was elected to Rhondda Borough Council in 1992, Mid-Glamorgan County Council in 1993, and, following the abolition of these, to the Rhondda Cynon Taf Council in 1996. She was elected to the European Parliament at the 1999 elections, becoming the first Plaid Cymru MEP. Evans was re-elected at the 2004 elections, in June 2009 and again in the 2014 election. She stood for the Rhondda constituency in the National Assembly for Wales election, 2007 and came second with 6,660 votes (30.1%).
Her party posts include national Chair of Plaid Cymru from 1994 to 1996. She is a long-standing supporter and member of the European Free Alliance (EFA), the pan-European grouping of Plaid Cymru's sister parties, which campaigns for independence for the historic nations of Europe and linguistic rights for minority languages.
In her first and second parliamentary mandates (1999-2004 and 2004-2009), Evans was vice President of the Women's Rights & Equal Opportunities Committee, a member of the Environment Committee and the Palestinian Delegation. During her second mandate, she was the President of EFA, and the first Vice-President of the Greens/EFA Group in the EP. Jill also deputised on the Delegation for Relations with the Palestine Legislative Council. She was also a member of the Committee on the Environment, Public Health and Food Safety and the Delegation for relations with Iraq, and deputised on the Agriculture Committee.
Evans has been lead rapporteur steering the parliamentary legislative process - and negotiating with the Commission, the Council of Ministers and lobbyists - for two EU Directives; extending the Pet Travel Scheme, ('pet passports') (2001) and updating ROHS (restriction of Hazardous substances) on electrical goods (2011).
On 4 November 2011 she was fined £575 after refusing to pay her TV licence fee in protest over changes to the Welsh-language channel S4C.
In the 2014-2019 parliament, Evans is the Vice-President of the EFA Group, and is a member of the Committee on Culture and Education. She deputises on the Transport and Tourism Committee. She is a member of the Delegation for relations with Switzerland and Norway and to the EU-Iceland Joint Parliamentary Committee and the European Economic Area (EEA) Joint Parliamentary Committee. She is Plaid Cymru spokesperson for European and International issues.
