It is certain that in or about 1115 a church was built or re-built because King Henry I granted by charter to Salisbury Cathedral, then located at Old Sarum, certain churches, amongst which were those of Coombe and Harnham. The north and south walls of the nave and chancel are Norman, as can be seen in the round-headed windows on the north side; also in the arch on the north side of the doorway leading from the vestry into the nave.
In the 14th century the small Norman chancel arch was enlarged, thereby cutting off parts of the stone nave altar and the semicircular recess with the wall painting of the Risen Chrst appearing to Mary Magdelene in the Garden, both of which can still be seen.
Also in the 14th century the chapel on the south side was built, dedicated to The Holy Trinity. In the west wall of the Trinity Chapel is a horizontal slit known as a leper squint, which provides a view of the altar for the benefit of any excluded from the building by reason of leprosy or excommunication. There was a leper house in Harnham in the Middle Ages. The fine 15th century wagon roof of the chancel has carved and painted heads and bosses.
Restoration was undertaken in 1873-4 by the well-known architect William Butterfield. The gallery was removed and pews, pulpit, reading desk and othe woodwork replaced by the present ones. The east and west walls were re-built. A new porch replaced the former leanto on the south side of the nave. The tower, re-built in the early 19th century, contains two bells, one 14th century and the other cast in Salisbury in 1692. All the stained glass windows, altar triptychs and two altar frontals are early 20th century work by the artist Eleanor Warre, who lived nearby at The Old Parsonage.