Gregory, formerly a professor a UC Berkeley, is the father of Dr. Hamilton Finn and Detective Harrison Chase. He was estranged for years from Finn because Finn slept with Gregory’s wife, Jackie, right before their wedding, and Finn was worried that Chase might be his son. Gregory thought that Finn was just angry with him for moving on too soon after his mom died. They have since reconciled.
Gregory and Jackie divorced. Gregory is also close to Finn’s daughter, Violet, and has recently started dating Alexis Davis. Gregory admitted to Alexis that he’s been diagnosed with ALS. Gregory is a smart, nice guy, much like his two sons. He would do anything for his kids or his granddaughter.