Jackie Harris's son, Andy, never actually existed as a fully realized character within the Roseanne or The Conners universe. This means he was never truly introduced or seen on screen during the show's run.
While Jackie's nephew, Jerry, has been a topic of discussion regarding his absence from The Conners, the case of Andy is different. Andy was an unseen or "retconned" character who was mentioned at various points but ultimately never materialized into a physical presence on the show. Consequently, he has not made an appearance in the spinoff series, The Conners, because he was never formally established as a tangible part of the on-screen narrative.
This situation is not uncommon in television, where characters might be mentioned in dialogue but never appear, or storylines are later adjusted or dropped. Andy serves as an example of a character who, despite being referenced, did not become a part of the show's tangible continuity. For more details on characters from Roseanne and The Conners and their continuity, you can refer to discussions about the show's missing characters here.
