By 1970, all three parish schools had experienced significant drops in enrollment. In addition, the dwindling numbers of Sisters of St. Joseph forced them to announce that they could not staff all three of the parish schools in the Highland area the following school year. As a result, the schools at St. Therese and St. Leo’s were incorporated into a new school, Highland Catholic, which opened its doors in September 1971 to a total of 460 students: 287 from St. Leo, and 173 from St. Therese. Eight years later, in 1979, St. Gregory also joined Highland Catholic School..
The 1990’s brought major changes in the structure of all three parishes. In 1994, under the direction of the Archdiocese of St. Paul and Minneapolis, the three parishes of St. Leo, St. Therese, and St. Gregory began a “clustering” process. Msgr. Terrance Berntson and Fr. Thomas Hunstiger were assigned as co-pastors of the newly formed Highland Catholic Community (HCC). In 1996, Fr. Jerry Grieman replaced Msgr. Berntson as one of the co-pastors. The Mass schedule changed so that there was no overlap among the three parishes. The HCC began using a common bulletin for the three parishes. Facilities were shared at all three sites.
In 1999, Fr. John Bauer was appointed pastor. A planning process began that eventually resulted in the full merger of the three parishes. At the request of Archbishop Flynn the parish name was changed to Lumen Christi. The St. Leo’s site was closed for renovation at the end of December 2004 and re-opened on Holy Saturday, March 26, 2005 under the new name of Lumen Christi. The Church of St. Gregory closed on May 15, 2005 and the Church of St. Therese closed on Sunday, February 5, 2006. The newly built Lumen Christi Parish Center opened February 11, 2006 for the first time. The parish was formally dedicated on April 23, 2006 by Archbishop Flynn.