Major Côté joined the Canadian Forces in June 1987. She graduated from Laval University in 1989 with a degree in Civil Engineering.

After her final training at Canadian Forces School of Military Engineering in Chilliwack, BC, she was posted in April 1991 to 5^ième Régiment du génie de combat in Valcartier where she was employed in various positions and particularly as a field troop commander. She has deployed in the former Yugoslavia (UNPROFOR) as a composite troop commander. Upon return she is appointed to the duty of Adjudant.

In 1994 she was posted as the Regular Support Staff Officer with 9^ième Escadron du génie de campagne in Rouyn-Noranda (Québec) as second-in-command. She then moved to Chilliwack at Canadian Forces School of Military Engineering where she occupied various positions within the Field Engineer Training Squadron. She was transferred to Gagetown, NB as the Canadian Forces School of Military Engineering is relocated where she became an instructor within the Tactics Section.

Promoted to her actual rank in 2001, she moves to the Royal Military College of Sciences in Shrivenham UK to attend the Technical Staff Course. Posted to National Defence Head Quarters in Ottawa in 2002, she was employed in various positions such as project director for the Relocatable Temporary Camps within J3 Engineer Operations, project director for the Chemical Agents Sensors within the section of defence nuclear, biological and chemical (NBC) and with Director Land Infrastructure (CLS) as Realty Asset and Business Manager.

Major Côté has accepted the position of Project Director for infrastructure projects within Secteur du Québec de la Force terrestre.

In 2008, Major Côté retired from the Regular Force and accepted the position of Project Director for infrastructure projects for the Land Force Quebec Area within the Canadian Army as a reserve officer. She has held this position to date under the Director Land Infrastructure and Assistant Deputy Minister (Infrastructure and Environment) following the transformation.

Johanne has accepted a job offer as a civilian employee and will continue to hold the position of infrastructure Project Director under the Director of Municipal Transfers and Project Development.