St Michael's Church was formerly a chapel of ease for Llangammarch before becoming the parish church for Llanfihangel Abergwesyn after the separation of that parish from Llanfan-fawr in 1864. Notably, prior to his conversion to Methodism by Howell Harris in 1740, Abergwesyn under the curacy of William Williams, Pantycelyn.

The medieval church was restored or rebuilt in the Early English style in 1871 at a cost of £4,200 by the architect R. J. Withers. It was laid out on a cruciform plan with a central tower with a pyramidal roof containing six bells, a southern porch and a large rose window to the western gable end of the nave. It contained several notable monuments to the Thomas family of Llwynmadoc dating back to the seventeenth-century.

The church was demolished in 1964, although the churchyard remains which contains a notable memorial cross to the Thomas family of Llwynmadoc. The medieval font was removed to Eglwys Oen Duw, Beulah (NPRN 421218).

(Sources: Edwin Poole, The Illustrated History and Biography of Brecknockshire From the Earliest Times to the Present Day (Brecknock: The Author, 1886), 161?62; Robert Scourfield and Richard Haslam, The Buildings of Wales: Powys (New Have, Yale University Press, 2013), pp. 423, 427; Cadw Listed Building Record, Ref No. 24532 (churchyard monument); CPAT Historic Environment Records, PRNs 4424, 20123)
A.N. Coward, RCAHMW, 18.04.2019