Darla was raised in foster homes, and the amount of time she spent shuffling from one place to another permanently impacted how she viewed herself. From the series' beginning, she was always Sally's faithful assistant. Although she had a soft spot for Clarke Garrison, in the end, her loyalty always went to Sally. After a brief failed relationship with Bill Spencer, Darla had little to do, other than a one-time fling with Clarke Garrison, for many years, until she ended up in bed with Thorne Forrester one night and became pregnant.

Thorne didn't realize what he was doing at the time, and Darla originally planned to have an abortion, but Thorne convinced her to give the child to him and Macy. After Macy chose Deacon over Thorne, Darla decided to keep the baby and raise it herself. Thorne, knowing he'd lost Macy, decided to lend a hand. When the little girl was born, she was named Alexandria in honor of Macy Alexander, who had died in a tragic accident. Darla and Thorne had formed a romantic attachment. Darla happily accepted when Thorne proposed, and the two were married in a beautiful ceremony.

It wasn't long before Darla was at odds with Ridge and Brooke. Ridge wanted her to keep her mouth shut about family business and to stay out of things, but Darla refused to let Ridge continue to belittle Thorne. While in Thorne's office one day, printing out some photographs from Sally's birthday, she set the envelope of photos on the desk while talking to Clarke, who was trying to convince her to steal the Ingénue line from Forrester. She didn't see Megan take her envelope containing Sally's birthday photos off the blotter and put it to the side and put the envelope with the Ingénue shots on the blotter. Darla accidentally gave the envelope to Sally. Ridge was furious, and made it clear that she was either a manipulator or a dingbat. Darla ran out of the room in tears and went home to pack her bags, but Thorne stopped her, swearing that no matter what, he would always love her, and didn't blame her.

While hosting a birthday party for their daughter, Ally, Darla responded to a phone call from her niece, Phoebe, whose car had a flat tire on Pacific coast highway. Darla went to help and tried changing the tire herself. When one of the lug nuts seemed stuck, Darla strained to pull it off. She fell backwards into the road and was hit by a car driven by Taylor, who was also coming to help Phoebe. Darla was brought to the hospital, but the doctors were unable to save her life.