There was a church on the site of St Mary's since circa 1328, erected by Henry de Gower, Bishop of Saint David's.

One Sunday morning, in 1739, the roof of the nave collapsed into the church while the congregation was waiting to enter the building.

The church underwent complete renovation between 1879 and 1882 by Vicar Dr Morgan.

[1] From the 1890s the Swansea Devil stood on a set of buildings facing the west side of the church, constructed by a disgruntled rival of Blomfield's, angry at the commissioning of Blomfield's designs over his own.

The tower contains eight bells, which were cast in 1959 by John Taylor & Co, Loughborough with the heaviest weighing 20cwt - 2qr - 12lb (1049.2 kg) in "E".