Deveau is a personal-care worker, who was employed at an adult residential centre before entering provincial politics.[1] Deveau defeated incumbent Richie Hubbard and former MLA Alex McIntosh to win the Yarmouth riding for the NDP in the 1998 provincial election,[2][3] becoming the first New Democrat to ever win a seat in western Nova Scotia.[4] As MLA, he was the NDP critic for Fisheries and Aquaculture.[5] He was defeated by Progressive Conservative Richard Hurlburt when he ran for re-election in 1999.[6][7]
Deveau attempted to win back the seat in the 2006 election, but was again defeated by Hurlburt.[8] In 2010, Hurlburt resigned as MLA, and Deveau won the NDP nomination for the by-election held to replace him.[9] Deveau's attempt to win a seat in the NDP government was unsuccessful, as Zach Churchill won the seat for the Liberals.[10] Deveau finished the by-election in fourth place, winning 6.5% of the vote.[11][12]