James Shaw is the co-leader of the Green Party of Aotearoa New Zealand. Voters elected Shaw to the New Zealand parliament at the 2014 general election as a list representative of the Green Party. The party selected Shaw as its male co-leader in May 2015.

In October 2017 the Green Party agreed to support a Labour-led government. Shaw became the Minister outside Cabinet for Statistics and Climate Change Issues, as well as holding the Associate Finance portfolio. Following the 2020 general election the Greens agreed to cooperate with the Labour majority government, and Shaw was re-appointed as the Minister for Climate Change.