Retreat leagues are a hallmark of the Passionist retreat tradition. It's not surprising, therefore, that Holy Family owes its existence to a retreat league.

A Passionist men's retreat league based in Connecticut formed in the 1920s. The league was affiliated with the Passionist Mother of Sorrows Monastery in West Springfield, Massachusetts. The league grew steadily until it numbered about 200 men. Then World War II broke out. Contrary to expectations, the league continued to grow during the war.

In 1945, league members approached Bishop Henry J. O'Brien of the Diocese of Hartford for permission to build a Passionist monastery and retreat house in Connecticut. Bishop O'Brien warmly received the league's proposal and gave his permission.

The league continued to expand; by 1947 it numbered over 3,800 men. In 1948 it became the Holy Family Retreat League that still exists today.

The league chose a hilltop pasture on the Farmington-West Hartford line as the site for the new monastery and retreat center. Construction began in the spring of 1949 and took just under two years. Father Joseph Leo Flynn, C.P., formerly of the West Springfield monastery, became director of the new Holy Family Passionist Monastery and Retreat Center.

Father Joe Leo welcomed the first group of retreatants, from West Hartford's St. Thomas the Apostle parish, to Holy Family on Friday, February 2, 1951. Since that first men's retreat over half a century ago, Holy Family has expanded its programming to include women, youth, music ministers, and people in recovery. Over 10,000 people attend Holy Family's programs annually.