During the time of the Galactic Republic, it was a member of the General Ministry Institutes.
Just before the start of the Clone Wars, the ExGal budget—along with the other General Ministry programs—was cut by 60%. This resulted in a greater use of droid exploration and a closing of several offices by the Society. Its president at this time was Tobbert Dalonbian.
By 25 ABY, ExGal had at least four listening posts, with ExGal-4 located on Belkadan. It was that outpost that finally discovered extragalactic life, in the form of an approaching Praetorite Vong ship. The Yuuzhan Vong subsequently destroyed ExGal-4 and killed all of its scientists, except for Danni Quee.