She was first elected in the 2005 election, garnering almost 50 percent of votes cast and 2,895 more votes than the next closest candidate. She was re-elected in 2009 to the new constituency of Esquimalt-Royal Roads.
In August 2007, Karagianis was appointed the Official Opposition Critic for the Ministry of Transportation in New Democrat leader Carole James' shadow cabinet. She had previously served as the Official Opposition Critic for the Ministry Children and Family Development, and, prior to that, the Ministry of Small Business and Revenue. Following the 2009 election, Maurine was again appointed as the Official Opposition Critic for the Ministry of Children and Family Development. In April 2011, Maurine was appointed Official Opposition Caucus Whip and presently continues to serve in this position.
Prior to serving as an MLA, she was elected as a municipal councillor in Esquimalt in 1996, and re-elected in 1999 and again in 2002. She is an entrepreneur, opening her own retail fashion store, operating a wholesale venture and a successful import/export business. She was also a co-founder of the Sunshine Folkfest in Powell River, BC.
Starting in 1998, she served three years with the provincial government as assistant to three NDP cabinet ministers – first in the Social Services ministry and then in Transportation and Highways. She recently ran a consulting company that works with non-profit organizations and First Nations communities to create affordable housing.