Chief Christiansen began his fire service career as a Volunteer Firefighter for the community of Campo in rural east county in 1995. He then became a Reserve Firefighter for San Miguel Fire and Rescue in 1996 before taking a temporary Firefighter position with the City of Coronado. In 2002, Chief Christiansen became a Firefighter with the City of National City where he was active in the Training Division and the Local. Christiansen promoted through the ranks with the City of National City until his return to San Miguel as a Captain in 2017. Christiansen currently serves as Battalion Chief over the Training Division.