Tributes paid to Dr Walsh's roles with the Irish Bishops Drugs Initiative, the Bishops’ Commission for Pastoral Care, Cura, and as Apostolic Administrator of the Diocese of Ferns.
Earlier this year the college and its grounds were sold to the GAA for a reported price of €95m.
Churches of almost every denomination hosted activities on Culture Night 2018.
According to Dublin diocesan archivist, Noelle Dowling, some of the material on display on Friday night includes photographs and letters of thanks and appreciation from Vietnam, which suffered devastation during 20 years of war from 1955 until 1975.
Ordained as a Holy Ghost Father, Joe Brennan served in parishes across the diocese of Middlesbrough as well as ministering in hospitals and prisons.