Scott entered the picture as a medical doctor working on Jessica Blair who was Christine Blair's mother and had AIDS. In 1989, Christine fell in love with Scott and they became engaged. The engagement was brought to an end when Christine discovered that Scott was her half brother, as the result of an affair between Christine's mother, Jessica, and Scott's father, Jim Grainger. Sheila Carter's obsession with Scott led to years of rivalry between her and Lauren Fenmore. Scott began dating Lauren. Christine was raped by Derek Stuart and pressed charges against him. Infuriated by the prospect of a long prison sentence, Derek cornered Christine with a gun. But as he pulled the trigger, Scott arrived and jumped in front of Christine taking the bullet for her. Scott's near death experience prompted him to propose to Lauren. They married in 1990, despite Lauren's feelings for ex-husband Paul Williams. Lauren suffered a miscarriage.
Scott was bothered, as he was unaware that Lauren was even pregnant. He turned to nurse Sheila Carter for comfort. Lauren and Scott split after she found out about his one-night stand with Sheila. Later Scott and Lauren decided to give their marriage another try, but both Lauren and Sheila then announced that they were pregnant with Scott's child. Sheila's baby was stillborn. Desperate to have Scott's child, she stole Lauren's newborn son and named him Scott "Scotty" Grainger, Jr. replacing him with a black market baby, whom Lauren named Dylan Lawrence Fenmore. Scott divorced Lauren and married Sheila. Sheila's mother, Molly Carter, discovered the truth about the "baby switch" and decided to tell Lauren. However, on her way to Lauren's office, Molly suffered a debilitating stroke which left her mute. Lauren began to visit Molly in the hospital, so Sheila formed an elaborate scheme to make it look like her mother had committed suicide. She then had Molly committed to a psychiatric hospital. Lauren's "son", Dylan, soon died of meningitis.
Worried that Molly would tell Lauren the truth, Sheila kidnapped both her mother and Lauren and held them hostage at a farmhouse outside of town. Intending to kill them both, Sheila confessed to switching the babies. She then set fire to the farmhouse, with Lauren and Molly barely escaping. Sheila was pronounced dead (assumed dead in the fire) and Lauren returned to Scott and Scotty. Lauren re-married Scott partly because she loved him but primarily to regain custody of her son. Later, Lauren was shocked to discover that Sheila was not only alive, but that she had proof of Lauren's affair with Brad Carlton, which would jeopardize Lauren's future custody of Scotty.
Later on The Bold and The Beautiful, Scott was diagnosed with a terminal illness which he kept secret from Lauren. When Lauren discovered Sheila to be alive and well in Los Angeles, she persuaded Scott to vacation with her on Catalina Island, so she could humiliate Sheila in front of her new husband Eric Forrester. Lauren was shocked to learn that Scott already knew that Sheila was alive, as she had visited him in the hospital shortly before. Lauren persuaded him to talk to Eric about Sheila, but an ill Scott died before he could say anything. His dying wish was for Lauren to move on with her life and to give Sheila a second chance. Lauren honored Scott's deathbed wish to give Sheila a second chance.
- Jim Grainger (father, deceased)
- Scotty Grainger (son with Lauren)