Harrington has led First Team Real Estate as its CEO since October 2023. Founded by board chair Cameron Merage in 1976, the firm serves Southern California with annual sales of more than $5 billion. Previously, she held the chief operating officer position after merging the brokerage she grew from two to 130 agents, Star Estates, with First Team. Harrington, a former Marine, also serves as a federal political coordinator for NAR and is involved with the California Association of Realtors and the Orange County Association of Realtors.