Henry Reagan is a retired Police Commissioner and the father of Frank, grandfather of Danny, Erin, Joe (deceased) and Jamie and great-grandfather of Nicky, Jack, and Sean. Henry is the Reagan family patriarch.
His childhood during the 1930s was hard due to his father's alcoholism and inability to hold a job. Henry was a Marine in World War II and Korea then joined the NYPD in 1952. Like his grandson, Danny, Henry is socially conservative and hates the political correctness of modern law & order. His wife Betty died December 2, 2001.
Henry had a hip replacement before the pilot and has difficulty getting up from a seat the first three episodes.
He had "a war cholesterol" before "knowing when to retreat". In the same episode, he also discusses a lot about the old days when he was commissioner, and the different expectations people had. He notes that even criminals didn't respect cop-killers.
He used to play handball and now likes to watch it, he taught Danny how to play as well.
- Len Cariou, separated in age from Selleck by only six years, wears make-up and a dental prosthetic for the part of Henry .