About Dan Conner
In the episode "Heart and Soul" in Season 9, Roseanne said that she had been with Dan since she was sixteen years old. According to the episode "PMS, I Love You", from season three, his birthday falls on the same day as the Illinois vs. Michigan game. In the same episode it makes it clear that Dan is turning 39. Given that season three takes place in 1990, Dan's birthday is November 10th, 1951. He is also the son of Audrey and Ed Conner, and the grandfather to Harris Conner Healy, Darlene and her husband David's daughter. He is a family man, and is shown in some episodes having a small temper. But overall, Crystal, in one episode, describes him as a huge teddy bear. He is a failed drywall worker, and a freelance contractor.
In season 3, his longtime friend Ziggy suggested that they begin a bike business. Unfortunately the bike shop, after about a year and a half, financially failed and was sold. Dan was crushed by this, and he suffered another blow almost immediately afterwards, at the start of Season 5: Becky, convinced that she was losing everything that mattered to her because of her parents' financial carelessness, ran away and eloped with Mark at age 17. Dan refused to even communicate with Becky for most of Season 5, and became increasingly restrictive and paranoid of Darlene as she and David drew closer; however, he was much more open to the idea of her going to art school in Chicago than Roseanne was.
At Darlene's wedding to David in season 9, he had a heart attack, which showed his terrible health, which had been declining over the seasons. He is the father-in-law to Mark and Kevin "David" Healy. At first he did not really care for Mark, but over the seasons, they bonded.
David and Dan had a rough patch when David lied about living with Darlene- which resulted in Dan manhandling him and kicking him out of the house- but Dan came to forgive him overtime when Roseanne pointed out that Dan was placing the blame entirely on David and ignoring that Darlene had been equally responsible. Although Dan increasingly became exhasperated with David's seeming over-sensitivity after he broke up with Darlene and often teased him about his less masculine and artistic interests, he was pleased with David's contributions to the household and congratulated him sincerely on graduating high school. They had another brief spat late in Season 8 when Dan learned Darlene was pregnant and planning to marry David, but Dan quickly reconciled with his newest son-in-law.
It was revealed at the end of the last episode of the show that Dan had in fact passed away from the heart attack that happened at Darlene and David's wedding.