To better serve the rapidly developing Oceanside area, until then served by Mission San Luis Rey and the downtown parish of Mary, Star of the Sea, the parish was established by the Catholic Diocese of San Diego in 1977 and dedicated to St. Margaret of Scotland. It's founding pastor was Father George Sproul (R.I.P.) Father William Gold (Ret.) served as pastor from 1978-2001, Father Cávana Wallace served as pastor from 2001 to 2021. Father William "Bill" Kernan serves as the present pastor and parish priest.

St. Margaret lived in the middle of the 11th century. She is venerated throughout the Church as a saintly mother, a fruitful wife and a model queen. She is an example of Christian discipleship especailly through her charity to the poor, particulary orphans. She was devoted to the Scriptures, a liturgist and had a active interest in sacred architecture and cival affairs, particulary during times of political unrest.