Religious worship in Castleknock dates back to 1185 when Richard de Tyrell, son of the first Baron of Castleknock, gave a grant to the Benedictine Monks of the Abbey of Little Malvern, Worcestershire, to endow a religious house at Castleknock in honour of St Brigid. In 1609, a Church was built on the site of this Abbey, and the present Church in turn replaced it. The foundation stone of the present Church was laid on 20th October 1803 and, with the help of a loan of £1,000 in 1809 from the Board of First Fruits, was completed in 1810. A spire was added to the tower in 1864 but was struck by lightning in 1957 and had to be removed.
The tower houses two bells. The smaller was cast in Dublin in 1855, while the larger was part of a ring of six in St Werburgh’s Church in Dublin City and was cast in Gloucester in 1747. St Werburgh’s tower was removed in 1836, as it provided a vantage point overlooking Dublin Castle, and was thought to be a security risk. The bell came to St Brigid’s in 1855.
Aras an Uachtarain lies just inside the Parish boundary and St Brigid’s therefore has a President’s Pew. This was regularly occupied by President Erskine Childers and was most recently occupied by President Mary McAleese on her official visit to the Parish in 1998.
St Brigid’s stained glass includes a window by Harry Clarke. This was ordered in 1927 at a cost of £270. The window includes three saints: St George, St Hubert and St Luke. St George is the patron saint of soldiers, of boy scouts and of England. He is shown wearing soldier’s armour. St Hubert grew up in the eighth century somewhat wild with a keen interest in hunting. Face to face with a stag, he was reminded of Jesus dying on the cross. He changed his ways and lived in the forest as a hermit before becoming a priest and then a bishop. St Luke was a Greek doctor who wrote one of the four Gospels and the Acts of the Apostles. He is the patron saint of doctors and surgeons.