It was then that Karen's mother, Nicole, was stricken with a brain tumor and died three months later. Devastated, Karen's life went in a downhill spiral. She began to hang out with shady people, and it was around this time that she met Zack Brady and got pregnant by him. Zack got Karen hooked on heroin and she used it for a year before her father found out. Alan had Karen put in a drug rehab center, where she spent six months of her life. When she returned, Zack had left town and Karen was once again clean. Life got back to normal until her father met and started dating Laura McKlain. Karen felt it was too soon after her mother's death for Alan to be seeing another woman. To make things worse, Laura had a son, Scott, who was into drugs. He and Karen fought constantly.

At that point, Karen decided the best thing for her to do was to move out. Rather than moving somewhere else in Pennsylvania, she packed her bags for Oklahoma and moved in with her aunt there. It was during the summer that she met John Ross and the two became good friends. After a few months, it was obvious to both of them that their relationship was more than just friendship.

In March 1998, while on a spring break trip to Galveston, John Ross proposed to Karen and they decided to fly back to Southfork where they would have their wedding.

Karen was thrilled, but definitely not prepared for life at Southfork. Almost immediately, J.R. began causing problems for her when he pried into her past and found out she was Alan Beam's daughter. J.R. didn't want his son marrying Alan Beam's daughter and vice-versa, so J.R. and Beam conspired to break up the wedding by revealing that Pamela Rebecca was pregnant with John Ross' baby.

From that point on, Karen and Pamela Rebecca were the worst of enemies. Pamela Rebecca constantly schemed to draw John Ross' attention away from her. Three months later, Pamela Rebecca took her scheming one step to far when she arranged with J.R. to have Karen's car sabotaged in order to prevent her from meeting John Ross. Pamela Rebecca fled to the hotel, drugged John Ross, and got him into bed. Karen arrived, late, to find them in bed together. John Ross awakened and left, taking Karen's car. He collided with another car and was in a coma for three months.

During that time, Karen grew close to Christopher and the two eventually slept together during the Oil Baron's Cruise. When they returned, John Ross had awakened and still thought that he and Karen were together. Karen and Christopher played along for a while, but soon told him the truth. On November 1, 1998, Karen and Christopher were married in Las Vegas.

They had to overcome several obstacles, including the revelation that the very baby that was responsible for breaking her and John Ross up, was actually Christopher's. Perhaps the biggest obstacle in their relationship was the one due to an event that took place on New Year's Eve. Drunk, Christopher went to a strip club with John Ross and slept with a stripper, Carla Thornton. Carla later announced that she was pregnant with Christopher's child. At that time, Karen began to get close to Eric Stone, Marilee's son. Little did she know, he and Carla were scheming to break up her marriage to Christopher. Karen slept with Eric, something she would later regret. Thanks to Todd Foster, Eric and Carla's schemes were exposed and Christopher and Karen got back together.

Christopher later became CEO of West Star, but decided to sell after missing a profitable business deal. Karen shredded the papers giving control of West Star to J.R. Christopher found out and the two had a fight. That night, Karen packed her bags and left for Pennsylvania, where she soon ran into none other than Zack Brady. Wanting for them to relive the time they spent together, Zack shot her up on heroin.

Whether Karen will be able to overcome her drug addiction again, remains to be seen.