The church was built in the 13th century to serve Ganns församling, a parish that seems to have dwindled early, with the building likely abandoned as a place of worship by the 1500s. Even so, it continued to be used occasionally for services into the 1600s, suggesting the ruin retained some significance to the local community long after its formal decline.
A well-known story associates the site with the Swedish hymn writer Israel Kolmodin. According to tradition, he arrived early to conduct a midsummer service here in 1692 and, while waiting, walked to the nearby Hångers källa (Hångers spring), where he is said to have been inspired to write the hymn "Den blomstertid nu kommer". This remains a cherished local legend rather than a documented historical fact, and visitors may enjoy walking the short distance to the spring, said to lie just south of the ruin.
The ruin itself was conserved in 1924, work that stabilised what remains of the stone walls and helped establish the site as a place of interest for visitors rather than an active place of worship. A separate, relatively modern freestanding wooden bell tower stands near the ruin, a simple addition that contrasts with the older stonework.
Today Ganns ödekyrka offers a modest but evocative glimpse of Gotland's medieval church history, valued as much for its atmosphere and associated legend as for its surviving structure.