In 1927 John McShain married Mary J. Horstmann (1907–1998). Over the years, the McShains began visiting Ireland and in 1956 acquired Kenmare House together with in Killarney (County Kerry). He and his wife extensively renovated the building and renamed it "Killarney House". In 1973, they gave Innisfallen Island and the ruins of its historic abbey to the government of Ireland. Five years later, Mr. McShain sold Killarney House and the greater part of the estate to the Irish State for a price well below market value at the time, having been assured that the house and estate would be incorporated into Killarney National Park. Mr. and Mrs. McShain reserved the house and surrounding 52 acres to their use for their lifetime. Mr. McShain died in 1989 and Mrs. McShain lived in the house until her death in 1998, when the house and surrounding land reverted to the Irish State. They are buried together in Philadelphia and commemorated with medallions at the Cathedral-Basilica of Sts. Peter and Paul. Their only child, Pauline McShain, became a Roman Catholic religious sister of the Society of the Holy Child Jesus. Having been empty for several years, the building fell into some disrepair. In July 2011 Leo Varadkar, the Irish Minister for Transport, Tourism and Sport, announced a €7 million restoration of the manor.