Elliot Stabler (Christopher Meloni) has been through a lot on Law & Order. The character was driven by his quest to find his wife's killer, for a time, but the focus has shifted towards the rest of his family in recent seasons, and the ways in which they shaped who he is.
Stabler's mother, Bernie (Ellen Burstyn), has appeared in several Law & Order: Organized Crime episodes, and the upcoming season will mark the introduction of his brother Randall (Dean Norris), but the one member of the family we've never gotten to meet is his dad, Joseph. What happened to the patriarch of the Stabler family?
Elliot's father was also a member of the NYPD
Joseph Stabler has cast a large shadow over Law & Order despite never actually being part of the franchise. Joseph was an NYPD detective during the 1960s. He was something of a stalwart in the department, but he was absentee father who was physically and emotionally abusive whenever he was around.
Elliot followed in Joseph's footsteps and joined law enforcement, but the more time he spent looking into his father's old cases, the more he came to realize that there was foul play involved. In the Law & Order: Organized Crime arc that plays out over season 2, Stabler discovers that his father and his old partner framed a kid for a shooting, and his father was subsequently given a Combat Cross for his efforts.
We never get a chance to hear Joseph Stabler defend his actions because he died long before the events of Law & Order: Organized Crime take place. He died decades ago, and the only time we see him is in the episode "Change the Game", where Elliot watches old home movies with his mother. Joseph is played by actor Tom Merlino in the home movies, though we rarely get to hear him talk.
Elliot's father was psychologically abusive towards him
It has never been revealed how Joseph Stabler died, but the Law & Order Wiki theorizes that the retired detective died shortly before Elliot joined the Special Victims Unit in 1999. This would go a long way in explaining why he never appears during the show's early years. It also lines up with the fact that Elliot alludes to his father being dead in SVU season 3, which aired in 2001.
Joseph Stabler is going to play a critical role in the upcoming season of Organized Crime. When TV Line announced that Stabler's brothers would be joining the show, it was revealed that the eldest, Randall, was still angry with Elliot over something that had to do with their father.
It's unclear what the "something" in question is, but given Joseph's checkered past as both a cop and a father, it's safe to assume that it's going to conjur up some unpleasant feelings for his sons.