In 1952 the Diocese of Columbus held the Western Deanery Meeting, now known as a Vicariate, at Ada High School. Then as now, the purpose of these meetings was to facilitate the collaboration of the parishes in the cities found in the district which at the time were Ada, Delaware, Kenton, LaRue, Marion, Newark, New Lexington and Portsmouth. In 1954 the church was enlarged with the addition of the sacristy on the north end of the building.

In 1965, under then pastor Reverend Francis X. Schweitzer, parish council was formed, the first in the Columbus Diocese. Father Schweitzer was known as the "priest of the migrant workers" because of his efforts to help migrant families with clothing drives, financial aid and medical care - especially for the children. Fr. Schweitzer developed the parish Newman Club and was also active as the advisor/chaplain for Ohio Northern University students of the Catholic Fraternity - Phi Kappa Theta at their "House on Irish Hill" at 825 S. Main Street in Ada.

Father Schweitzer's successor, Father Leo Benedetti initiated an active remodeling campaign in 1967 with the installation of new pews and carpeting, a new altar facing the congregation and new coat of paint for the entire interior of the church building. Because of expanded needs of the church building, Father Benedetti considered several options for the future of the parish. One option was the building of a new church and a hall on West Lima Avenue. The other option that was considered and eventually was pursued, was the adding of a new connecting hall to the existing church structure with the rectory closer to the church. The parish rectory had been located at 508 North Main Street since being purchased in August 1948.

In 1969, Father Samuel Durbin came to Our Lady of Lourdes and sold the Main Street rectory and purchased the current rectory at 222 E. Highland Avenue. In addition to his duties at Our Lady of Lourdes, Fr. Durbin was a National Guard Chaplain and a recognized gardener. When Father Durbin was transferred back to Columbus in 1971, Msgr. Joseph McGlynn became the parish pastor. Father Richard Endres became the pastor of Our Lady of Lourdes in 1973.

Under the direction of Pastor Richard Endres, the two story connecting hall on the east side of the church became a reality and was dedicated by Bishop Herrmann on December 8, 1974 during the parish's Centennial celebration. Fr. Endres is also fondly remembered for his leadership and vision in supervising the celebration of the parish's Centennial in 1974. Fr. Endres passed away on July 6, 1977 and was succeeded after a time by Father Arthur Wiles. On July 6, 1978, the church hall was rededicated in honor of Pastor Endres and is known as Endres Hall to this day.

During the ten years that Father Wiles was at OLL, Jack Stahl was ordained as a Deacon and Father Stephan Moloney became the first Ada resident to become an ordained priest in 1982. Father Wiles was known for his interest in scuba diving, his labrador named Matthew and his famous bean soup featured each year at the parish bazaar every November.

Father Wiles initiated the inclusion of girls as Mass servers. His weekly Saturday evening service became known as the "ONU student Mass" with one of the highlights being the student choir's singing of "Peace I leave with You, My Friend." The Saturday evening Mass became so popular that for a time in 1980, President DeBow Freed of Ohio Northern University began following students to the church each week to see where they were all going.

In 1987, Father Thomas Kessler became Our Lady of Lourdes Parish's ninth resident pastor. During 1990 and 1991, Father Kessler initiated many needed improvements for the church. Father Kessler supervised the installation of a new heating and air conditioning system, a complete replastering job for the church's interior, new front doors and new steps in front and back and the construction of the parish parking lot immediately south of the church.

Father Ted Thomas came to Our Lady of Lourdes in 1992 and immediately became known for his wit and humor. Father Ted always ended each Mass with a joke that made a point for parishioners to consider as they left the church each week. As did both Father Wiles and Father Kessler before him, Father Ted became well known to ONU students through his teaching on campus. Fr. Ted taught courses in Western Civilization and as with his weekly sermon, Fr. Ted was able to bring his points alive with his descriptive abilities, his wit and humor.

Father Daniel Millisor came to Ada in July 1996 and has continued the tradition of serving the Catholic community of the Ada area and Ohio Northern University. In early 1997, Father Millisor coordinated a parish dinner to commemorate the feast day of the parish's patron on February 11. Bishop Griffin of the Diocese of Columbus attended the dinner and wished the parish well in its one hundred and twenty-third year of existence. Father Millisor brought the parish to the information superhighway with the introduction of the parish webpage on February 28, 1997. Fr. Dan established the parish's 125th Anniversary Committee and provided strong support to the committee in its planning and implementation stages throughout 1998 and 1999.

The year-long festivities began in January 1999, ending with a celebratory Mass on December 8, 1999, hosting Bishop Griffin and other parish guests. The Holy Year 2000 was celebrated as a Jubilee Year. In early 2002 Father Dan announced to the parish that Bishop Griffin had reappointed him to serve another six year term as pastor ending in 2008. However, in December 2005 Fr. Dan announced that the Bishop had reassigned him to another parish near Columbus beginning in March 2006.

Father David J. Young was named Our Lady of Lourdes' 12th resident Pastor in March, 2006 and left for St. Pius X in Reynoldsburg in the summer of 2018.

Father William J Ferguson became Pastor of the Cluster of Our Lady of Lourdes Parish and Newman Center and Immaculate Conception Parishes that same year, 2018, with Father Jeffrey Tigyer continuing as Parochial Vicar. Fr. Ferguson moved on to St. Andrew parish in Upper Arlington, Ohio in July 2020. 

Deacon Mike Hood celebrated the 10th Anniversary of his Ordination to the diaconate in November of 2019 and our parishes were blessed with the ordination of OLL parishioner Nick Klear to the diaconate on Nov 7th, 2020. 

Father Ed Shikina arrived as pastor of Our Lady of Lourdes in Ada and Immaculate Conception in Kenton, as well as chaplain to the ONU Newman Club on July 14, 2020. He helped guide the parishes through the COVID-19 Pandemic and Real Presence, Real Future initiative. Fr. Ed left to become the pastor of St. Mary's in Marion and Sacred Hearts Catholic Church in Cardington in July of 2023.