When Hart Jessup's grandfather died, he thought his whole world would fall apart. Their farm was gone to some big wheel who tricked his grandfather, his mother was dead and he never knew his father. While going through all of his mother's letters that she wrote to her dad during her days in the "Agency", Hart found out who his father was and arrived in Springfield in search of a new family. He found out that his dad was married to Alex Spaulding and took a job in the Spaulding stables and eventually revealed himself to Roger Thorpe as his son.

Hart was a good man with a good heart, but that was hard for people to believe considering that his father the infamous Roger Thorpe. Later, when Hart learned that Roger was the one who stole the family farm from his grandfather, he was furious. After telling Roger that he hated him and never wanted to see him again, a devastated Hart got drunk with Bridget Reardon in the stables and they had sex. Unbeknownst to Hart, Bridget ended up getting pregnant but Hart wouldn't know that until years later since immediately after their love making, he left town.

When Hart returned and learned that he had a son, Peter, Hart tried to make up for lost time by being a father to his child since he didn't have either parent growing up. Meanwhile, when a Wealthy Henry Chamberlin left Hart most of his fortune in his will because he believed in him, Hart became a very wealthy man. Still angry at his father, Hart decided to help Roger's current wife, Dinah Marler, drive Roger crazy and steal back all of Dinah's money that Roger had stolen. The plan ultimately worked when Dinah received Roger's power of attorney and gave Hart his farm back. He began falling in love with Dinah and soon she reciprocated. They did get all her money back and started their lives together. Hart and Dinah were happy for a time, but when a newcomer arrived in Springfield, Hart's feelings once again were in question.

The newcomer was Cassie Layne, who had started working at Lewis Oil as a secretary and was a single parent to her daughter Tammy. The two fell in love and Hart finally broke it off with Dinah, who became livid. Desperate to keep Hart, Dinah got pregnant by another man and told Hart it was his. Out of obligation, he began to go to doctor visits with Dinah and the two became very close. However, when Hart slammed a door open at the Lewis's, Dinah was knocked out. Tragically, she lost the baby and began making Hart feel responsible for everything. Later, Dinah took her mother's hypertension medication in order to make herself sick. It worked and Hart felt so bad that he married Dinah, believing that she was going to die. When Dinah got better, Hart wanted to get back with Cassie but every time he tried, Dinah would manipulate the situation. Hart finally told Dinah that he was leaving her when he found out that Cassie was pregnant with his child, and that Dinah had known the entire time.

Hart ran to Chicago and made it just in time to see his son born. Hart took Cassie and the baby, who they would later name Roger Joshua, back home. Hart left Dinah and he and Cassie moved back to the farm. After Dinah came over acting crazy as usual, Hart told her not to come back, ever. Unfortunately, she did and tried to kill Cassie. Hart came in just as Dinah admitted that the baby that died was not his, and jumped in front of the gun as Dinah fired at her rival, Cassie.

Hart was shot close to his heart and was told that it would be a while before they could remove the bullet, so he was told not to move. At some point, Dinah snuck into the hospital and tried to convince Hart that she did not mean to hurt him; it was all Cassie's fault. When he told her it wasn't Cassie's fault and he tried to call for the nurse, Dinah got upset and began shaking him. This led to a cardiac arrest. Dinah fled and Rick worked on Hart. He brought him to and Hart began seeing an angelic "guide" who tried to help him find his way. Hart rejected the vision and made a promise that he would fight for his and Cassie's life together. Unfortunately, when he finally did have the surgery, something happened and the blood supply was cut off to his over 20 minutes, leaving Hart with brain damage. Cassie praying over Hart, realized that he was struggling for her and their family and decided to let him out of his promise to her and let him die.