Gregg was an employee at the Bay Mirror and was one of Phoebe Halliwell's colleagues and friends. As many other co-workers, he deeply missed Phoebe after her "death" in 2005. In Run, Piper, Run, it was mentioned he had a baby daughter.
Later, Phoebe (using the alias of Julie Bennett) asked him to make a report about unexpected earthquakes. Despite the physical disguise, he found her behavior quite familiar with Phoebe's.
Gregg appeared in a total of 2 episodes over the course of the series.