Herron was a senior member of the
Independent Democrats. In July 2008, he was elected policy convenor of the party's Cape Town metro district executive committee. Herron was then sworn in as a Cape Town city councillor for the ID. The ID announced its merger with the
Democratic Alliance in October 2010 and Herron was given dual party membership. After the
2011 municipal election, he was sworn in as a councillor for the DA. De Lille was elected mayor of Cape Town, and she appointed Herron as the mayoral committee member for transport and urban settlements. In August 2018, De Lille announced that she would resign as mayor at the end of October. Herron declared his candidacy for the post, but the DA selected
Dan Plato. On 1 November 2018, he resigned from council and from the DA. He was the ninth councillor to resign from the DA following De Lille's last address as mayor on 25 October. De Lille announced the formation of her new political party,
Good, on 2 December. Herron was appointed as the party's inaugural secretary-general on 20 January 2019. Prior to the
general election on 8 May 2019, he was second on the new party's provincial candidate list, second on the regional candidate list and fourth on the national candidate list. The party won one seat in the provincial parliament and Herron filled that seat on 22 May 2019. On 22 August 2021, Herron was announced as Good's mayoral candidate for the
City of Cape Town for
the municipal elections on 1 November 2021. The DA retained their majority on the city council and Herron remained a member of the Provincial Parliament. == Parliamentary career ==