[2] The church is notable for its Victorian architecture, medieval remains and a surviving 11th-century motte-and-bailey castle mound located within the grounds.

[3] The church has been on the Heritage at Risk Register since 2013 due to substantial works required to repair the building.

[8][9] The architect of this church is unknown, but surviving photos indicate it was a short, wide structure of six bays in the Georgian style.

[6] Distinguished architect Sir George Gilbert Scott designed the replacement and the foundation stone was laid on Easter Monday, 1869.

During construction, the preserved pillar in the vicarage garden was included within the choir vestry of the new church by Scott.

Scott made a minor alteration to the old tower, replacing the late Georgian battlements and pinnacles installed in 1826 with a slate-covered pyramidal roof.

[2][6][9] The church has a variety of fittings, including Victorian choir stalls, two fonts, an alabaster reredos and oak pulpit.

The pulpit, made of carved oak on a stone base, depicts John the Baptist, Paul and Augustine of Canterbury.

[2][6][7][8] Externally, the church is constructed from ashlar quarried from nearby Huddersfield, with slate roofs throughout except atop the tower, which is lead.

[6][16][17][18] This organ still forms the core of the present instrument but has received overhauls, enlargements and repairs multiple times.

Firstly, in 1946, Walker & Sons returned to overhaul the instrument and make provision for a larger 16ft Contra Gamba but this pipe was never added.

A more major overhaul took place in 1963, again by Walker & Sons, who dismantled and rebuilt the instrument with new second-hand pipes in the pedal section.

This overhaul, taking place in 1986, cost over £24,000 and involved replacing the piston system, tonal adjustments and additional stops.

[21] When the present building was opened, these bells were transferred to St Michael & All Angels, Thornhill, West Yorkshire.

[21] Thornhill replaced these bells in 1980 with another second hand ring, a peal of eight cast by Charles Carr of Smethwick in 1910, originally hung at St Paul's Church, Todmorden.

[22] Only one of the bells from Mirfield's old church still survive; the treble, cast by Daniel Hedderly of Lincoln in 1725 was purchased to augment the ring of five at Cropwell Bishop, Nottinghamshire; the other five were scrapped in 1980.

[22][23] During construction of the present church, a heavy peal of ten bells was cast by John Taylor & Co of Loughborough in 1869, installed in October 1870 when the tower was high enough to house them.

This ring of ten, with a tenor of 30 and a half long hundredweight (1,550 kg)[24] were first rung on 15 July 1871.

[29][11][30][31] The restored and recast bells arrived back in Mirfield in March 2016 and were first rung just after Easter.

[32] The result has been hailed as "superb"[33] and the bells at Mirfield are now considered "amongst the finest rings of ten in the country".

The body of the old church, demolished in 1873, now houses a memorial garden and there is a 12 feet (3.7 m) high stone cross near the main porch commemorating the First World War.

[6][36] The most significant feature in the churchyard is the surviving 11th-century motte from a motte-and-bailey castle, located just behind the present church tower.