[4] Prior to his election to the legislature, he worked for the Nishnawbe Aski Nation in Sioux Lookout.

Mamakwa was one of three MPPs of Indigenous heritage elected in 2018, alongside ONDP colleagues Suze Morrison and Guy Bourgouin, and the second person of full First Nations descent elected to the assembly after Peter North in 1990.

[5] On May 28, 2024, Mamakwa became the first person to give a speech in an Indigenous language in the Ontario Legislature.

Mamakwa spoke for 10 minutes in Anishininiimowin (Oji-Cree in English) at the start of question period.

[6] [7] As of August 11, 2024, he serves as the Deputy Leader of the Official Opposition and critic for Indigenous and Treaty Relations as well as for Northern Development.