As an organization born in the heart of the Catholic Church, the Legionaries of Christ's mission is to bring Christ's redemptive message to every heart, and to imbue every human endeavor with the spirit of the Gospel. Its mission is to extend Christ's Kingdom in full collaboration with the Church and its bishops. The Legion of Christ's goals and activities are primarily spiritual, transcendent, and salvific.

The wide range of apostolates available to members include: missions, service projects, educational works, catechetical schools, youth and family ministries, works of cultural transformation, and mass media projects so that each member can devote their own talents to the mission.