Provided are a computer program product, system, and method for managing write operations to an extent of tracks migrated from a second storage to a first storage. An extent object exists if the extent was previously migrated from the first storage to the second storage at a previous time. In response to determining that the extent object exists, a determination is made of the tracks in the extent having a write indicator indicating that the track was updated in the second storage since the previous time. The data for the determined tracks is copied from the second storage to free locations in the first storage. For each determined track, the entry for the determined track in the extent object is updated to indicate the free location to which the data for the track was copied as an active address for the track.