Prior to her election, Popham owned and operated the organic grape orchard, Barking Dog Vineyard, on Vancouver Island.

[11] She began campaigning for the 2008 municipal election but withdrew to run for the provincial NDP nomination in the Saanich South riding.

[12] The riding's Member of the Legislative Assembly (MLA), New Democrat David Cubberley, had announced he would not run in the next election and party rules required that his successor be female.

The Saanich South election was expected to be one of the closest in the province,[11] with Popham facing former CHEK-TV reporter and news anchor and BC Liberal candidate Robin Adair,[13] lawyer and Western Canada Concept Party leader Doug Christie, and Green Party candidate Brian Gordon.

[16][17] She joined with fellow NDP MLAs Scott Fraser and Claire Trevena, in conjunction with the Western Canada Wilderness Committee, in lobbying for the stop to old-growth logging on Vancouver Island and the Lower Mainland.

Under Dix, Popham remained agriculture critic and they advocated for health authorities to use local food in hospitals,[23] reinstating the Buy B.C.

[28] Popham opposes the commercial production of the genetically engineered Arctic Apple, arguing it could negatively affect the reputation of BC fruit.

[29] She is a leading proponent of increased protection for native pollinators and honey bees on Vancouver Island, maintaining a blog on the subject.

Party leader Adrian Dix appointed Popham to a critic role focusing on small business, tourism, arts and culture.

Her NDP formed a majority government in the ensuing 42nd Parliament and Premier Horgan kept Popham in the Executive Council, but renamed her role to Minister of Agriculture, Food and Fisheries.