The Congregation began its apostolate in Kaesong Parish, where the Congregation was founded, in the Seoul Vicariate Apostolic. After the Korean War, Korean society suffered economically but the Church in Korea grew rapidly, and parishes across the country requested sisters. Thus, the Congregation began sending out sisters in 1951 first to Tongyeong Parish (now Taepyeongdong Parish) in the Masan Diocese in 1951; now it works in apostolates in 66 parishes in 15 dioceses, solidifying its position as a national Congregation.

Recognizing the need for education to realize concretely the spirit and mission of the Congregation, we started early childhood education and opened a kindergarten attached to the parish in Huam Dong, Seoul, in 1955. Today, we have apostolates in 14 parish-affiliated kindergartens and three of our own kindergartens. In 2003, we established and are operating the Bokja Montessori Teachers' Institute not only for early childhood education, but also for the purpose of training educators who possess character, qualifications and professionalism and who are in charge of early childhood education.

In 1961 and 1963 respectively, we founded the Bokja Girls’ Middle School and the Bokja Girls’ High School in Cheonan devoting ourselves even to the education apostolate for women. Even today with standardized education, these schools are well-known locally.

The Congregation is practicing social welfare apostolates focusing on the vulnerable in various social levels. From 1963 to 2005, we directly operated Our Lady of Mercy's Hospital in Bupyeong (now St. Mary's Hospital Incheon), and after presenting it to the Diocese of Incheon, we are cooperating with the diocese now in its management. We continue our apostolates for children, youth and those with disabilities at Our Lady of Mercy’s Dream Hill (from 1985) and at Our Lady of Mercy’s Welfare Center from 1990, etc., that we are running.

In addition to these apostolates, we began pastoral care for the Korean community in Osaka, Japan, in 1967. Celebrating the 200th anniversary of the founding of Korean Catholic Church 1984, the Church in Korea exhorted all of us to commit to missionary work overseas, so in 1987, we began sending our members to Mexico. Today, we are serving overseas missions in 11 countries on five continents.

Keeping alive the purpose and intention of the founding our Congregation (which is to carry on the spirit of the Korean martyrs) with a special sense of duty since our founding, we have been cooperating even in projects promoted by the Church in Korea to exalt the martyrs. We are laboring, of course, in collecting and preserving relics of the martyrs, developing and managing martyr shrines, but also in education in the spirituality of martyrdom and the development of related programs.