Grigson was fired in January after spending five seasons with the Colts.
"Ryan brings valuable experience to our personnel group," Browns executive vice president of football operations Sashi Brown said in a team statement. "He was raised as a road-scout and has been evaluating talent in this league for almost 20 years. We place a premium on that experience and on his passion for football. Ryan has much to offer to any personnel department and we are pleased that he chose to join our staff."
Grigson will work as the senior personnel executive with the Browns. He will report to Browns vice president of player personnel Andrew Berry.
"We are excited to add Ryan to our personnel department," Berry said in a team statement. "Having worked with him for four years with the Colts, I know Ryan is an individual with a palpable passion for scouting, a tireless work ethic and an insatiable competitive drive. His experiences as an NFL player and executive will prove valuable to the mission of our group, while his team-orientation and personal integrity will continue to strengthen our department's culture."
Grigson has 19 years of NFL front office experience. The 2012 Sporting News NFL Executive of the Year has worked for the Philadelphia Eagles, St. Louis Rams and in the Canadian Football League and Arena Football League.