When he was 17, in response to the dismissal of several popular teachers, Zimmerman took part in a demonstration in which protesters barricaded the building.

[1] The project was converted into a company, Designing Hong Kong Limited, founded by him together with Christine Loh, Peter Wong and Markus Shaw.

He retired from the position to focus his efforts on Designing Hong Kong and the Southern District Council.

[3][4] He is currently the vice-chairman of the Coalition on Sustainable Tourism and Chairman of the Single-Use Beverage Packaging Working Group, best known for its initiative Drink Without Waste.

[4] In 2006, lawmakers Audrey Eu Yuet-mee, Albert Lai Kwong-tak and Ronny Tong Ka-wah asked Zimmerman to join the Civic Party as a founding member.

He later won a seat in Pokfulam in the Southern District Council in a by-election in 2010, succeeding Ronald Chan Ngok-pang who resigned after being hired by the Chief Executive's Office.

[5] In the 2016 Legislative Council election, Zimmerman ran in Hong Kong Island as an independent democrat.

[7] He joined 20 other electors (from the 1,194 total) in nominating former judge Woo Kwok-hing for Chief Executive in the small-circle 2017 election.

In the 2019 District Council election, Zimmerman successfully won his re-election bid in the Pokfulam constituency, with 2,547 votes.