Karissa is a third culture kid (TCK), born in Canada who grew up in South America where her parents were serving as international workers with the C&MA. She was first connected into the Foothills family when she was a young girl coming back to Canada for a home assignment.

At age 18 Karissa sensed a call into full-time ministry. However, the next six years felt like a "long dark night of the soul" where she wrestled deeply with depression, doubts, and a God who seemed silent. In 2011, Karissa attended a seven-month YWAM school in Germany, during which God began to heal her heart as well as redefine her concept of missions. She came back to Canada knowing she is called to journey alongside people towards healing, wholeness, and freedom in Christ, and also that that calling is not to Canada.

In March 2015, Karissa joined Ralph & Ruth Shareski in Heidelberg, Germany, and continues to work there as a career international worker. She is part of the team lead the ministry called New Song HD. The ministry focuses on discipleship training, leadership development, evangelism, planting missional communities, and fanning the flame of unity and prayer.