[1] As the BC New Democratic Party were preparing for the up-coming 2005 provincial election, Macdonald put his name forward as a potential candidate for the Columbia River-Revelstoke electoral district.

[2] At the November 2004 nomination meeting, attended by party leader Carole James, in Windermere, Macdonald was selected, with a 75% vote, over Kimberley-resident Brent Bush[3] to be the BC NDP candidate.

[5] The incumbent MLA, Wendy McMahon of the governing BC Liberals, was promoted to a ministerial position (Minister of Women's' and Seniors' Services) in December 2004[6] and major improvements to Kicking Horse Canyon Highway and rural roads were announced.

[44] Macdonald continually lobbied Minister of Environment Barry Penner to re-acquire a conservation officer for Golden, a position that had been eliminated.

Legislative changes made in 2006 by the BC Liberal government promoted the development of private power projects on formerly wild rivers and creeks.

[58][59] On May 26, 2008, Macdonald presented a petition signed by 1000 Golden and Area residents stating their opposition to a power project at Thompson Falls.

[60] The largest proposed private power project in the area was Glacier/Howser which was heavily opposed by Columbia Valley residents[61] which resulted in even larger protest events being organized in Invermere.

[67] Macdonald and Mair also dropped in to Selkirk Secondary School in Kimberley to meet with students to discuss environmental and social issues.

[69][70] While visiting Golden on another file, the Minister of Environment was met by a large group of protestors who wanted local rivers and creeks protected from private power developments.

[73] As the 2009 provincial election approached, Macdonald was acclaimed as the NDP candidate[74] and Revelstoke mayor Mark McKee won the BC Liberal nomination.

[75] BC Conservative leader Wilfred Hanni announced his intention to run in the riding[76] but later switched to neighbouring Kootenay East.

[86] Macdonald joined local opponents and the Western Canada Wilderness Committee who sought to block logging operations in the Mount Arrowsmith UNESCO biosphere reserve near Nanoose Bay.

[98] During the subsequent leadership election, Macdonald endorsed Mike Farnworth calling him "competent, ethical (and) responsive to the issues that the people feel are important".

[102] The result ended up closer than expected and though Macdonald won the Columbia River-Revelstoke seat, his NDP again formed the official opposition to a BC Liberal majority government in the 40th Parliament.

[103] After NDP leader Dix resigned, Macdonald again endorsed Farnworth as a suitable replacement,[104] though John Horgan would go on to win the 2014 British Columbia New Democratic Party leadership election.