In August 2000 he became Chief of Staff to party leader Tony Leon - a position he served until June 2004, when he became Assistant to the Chairperson of the Federal Executive.

The result allowed Helen Zille to become Premier of the Western Cape, and saw the DA take control of the provincial legislature in an alliance with the Independent Democrats.

[10] On 27 March 2013 Maynier led the thrust for a parliamentary inquiry into the SANDF's intervention in the Central African Republic coup.

[13] On 9 December 2019, Maynier announced the establishment of a task team to address congestion issues at the Port of Cape Town container terminal.

[14] On 22 April 2022, premier Alan Winde announced that Maynier would be taking over from Debbie Schäfer as the Provincial Minister of Education when she leaves office on 15 May 2022.

DA chief whip Mireille Wenger would then replace Maynier as the Provincial Minister of Finance and Economic Opportunities.