Joseph "Joe" Conor Reagan is the deceased son of Frank Reagan. He was the third child of the Reagan family. Badge Number: 46808
Joe Reagan was an NYPD Police Detective who died in the line of duty on May 15, 2009 (15 months before the beginning of the series). Joe was involved with the Federal Bureau of Investigation investigating a group of corrupt NYPD cops, who were operating within a fraternal organization called "Blue Templar ".
The corrupt cops murdered Joe when his covert investigation was getting too close to naming names. Joe served as NYPD warrant officer for 10 years before his death. His training officer, Anthony Renzulli, called him a 'real sweetheart' implying he was more like his brother Jamie than his older brother Danny.
Although never married, he dated Angela. After his death she moved, only to later come back and marry a Detective from narcotics. Out of respect for Joe she invited the Reagan family to the wedding.
- Joe's age is one of the worst continuity errors of the show. His headstone clearly indicates that he was born in 1977, which would place him as the third Reagan child yet he has been called the oldest at least once. Since Erin celebrated her 40th birthday in November of 2015 (The Bullitt Mustang) Joe would be approximately 19 months younger than her and Erin is acknowledged to be younger than Danny by approximately two years (Reagan v. Reagan, Cellar Boy to name a few references).