The need for a new church in Welwyn Garden City was found as the town expanded in the 1950s towards Sherards Park Wood and Digswell. A site for the church was allocated at Shoplands, part way down the slope to the Mimram valley. Initial plans were drawn by De Soissons, Peacock, Hodges and Robinson in 1959 but these differed substantially from what was actually built. Louis de Soissons was instrumental in the original designs for Welwyn Garden City having created the Master plan in 1920 when he was appointed architect for the town. He died in 1962 after the initial plans for Holy Family church had been prepared but before the start of construction.

Holy Family church was opened in 1967. Originally it had a railed sanctuary, high altar and provision for a baptistery at the west end. Plans for re-ordering were prepared by Harold Barker in 1973. These included removal of the high altar and creating a smaller forward altar, removal of the communion rails and the Lady altar.

The sanctuary floor was re-laid by James Keegan for the dedication of the church by Cardinal Cormac Murphy O’Connor on 13 May 2007.

The design of the church is marked by a tall bell tower at the southeast corner. The plan consists of a eastern narthex, a wide aisle-less nave, a square-ended sanctuary with a sacristy leading off the north side to the presbytery. The walls are of local brick and the roofs are copper clad. The east end has a gabled porch with two entrances.

The entrances lead into a small lobby area. The main space is entered under the east gallery, which has an open ironwork and glass front. The walls are of bare brick throughout, and the floors of patterned black and white marble in the sanctuary and grey/green and cream linoleum in the nave. The church is furnished with a square stone font with circular polished brass cover, simple communion rails (without gates), and gilded fibreglass statues of the Holy Family and Our Lady by Gordon Beningfield. At the east end are statues of St Patrick and the Sacred Heart, the latter by Mayer of Munich. The seating consists of plain open-backed benches.