Children: Lily Montgomery (adoptive), Reggie Porter Montgomery (adoptive), Greenlee Smythe du Pres (with Mary Smythe)
Siblings: Travis Montgomery (deceased), Christine "Kit" Montgomery
Niece: Bianca Montgomery, Molly Montgomery
Nephew: Matthew Montgomery
Sister-in-law: Barbara Montgomery
Significant Romantic Relationships: Brooke English, Angelique Marick, Laurel Banning (divorced), Erica Kane

Jackson Montgomery came to Pine Valley in 1987 as an unscrupulous attorney who helped his brother Travis win the race for Senate. Ultimately, Jack's mismanaging of funds brought about Travis' political demise and his brother resigned before the truth was made public.

As his brother's marriage to Erica Kane hit trouble, Jackson's feelings for his sister-in-law grew. Erica eventually told Travis that she would not fight their divorce and Erica and Jack headed off on a business trip to Los Angeles together. On the way, Jack and Erica's plane crashed in the desert. While stranded, the two realized the depth of their feelings for each other. When Erica and Travis divorced, Jack and Erica were free to continue their romance. Erica's daughter Bianca, however, did not like the idea of her mother and her Uncle Jack together. As Erica and Jack planned their wedding, Bianca fell ill with Reye's Syndrome. The illness brought Travis and Erica closer. With Bianca's interest at heart, Erica started to date Travis again, but agreed to see Jack on alternate nights. Eventually Jack gave Erica an ultimatum: Travis or him.

Erica headed off on a cruise to make up her mind and upon her return she chose to marry Travis. Jack arrived at Erica's small wedding to Travis, with plans of taking her to Paris with him. Erica stopped the wedding when she saw him, but she bid him farewell in the church vestibule before she married Travis for the second time.

Despite Erica being married to his brother, it appeared that Jack and Erica were not over each other. When Erica learned that Travis and his ex-wife Barbara were having another baby together as a bone marrow donor for their daughter Molly, she and Travis broke up once again. Over concern for Bianca, Erica and Travis did not divorce and Erica began an affair with Jack. Bianca saw her mother and Jack in an embrace and set fire to her dollhouse. The whole house caught on fire and Erica was almost killed. Travis learned of Erica's affair with his brother and divorced her.

Travis sued Erica for full custody of Bianca, with plans of taking Bianca to live in Seattle. After Jack told the truth on the stand about his affair with Erica, Travis was awarded full custody of Bianca. Angry that he would not lie in court, Erica told Jack that she never wanted to see him again.

After his break up with Erica, Jackson took up with Brooke English, much to Erica's chagrin. Jack and Brooke's jealousy over each other's past flames plagued their relationship and they amicably parted ways. Jack then entered into a brief relationship with Dimitri Marick's wife Angelique, but her complicated past with Dimitri spelled the end for that relationship.

Jackson met former con artist Laurel Banning and there was an immediate attraction. Jack helped Laurel cover up the death of her abusive ex-husband, Denny, which resulted in his temporary suspension from practicing law. Soon, the two were in love and married, with Jack adopting Laurel's autistic daughter Lily. Jack's unresolved feelings for Erica as well as Laurel's growing interest in Trevor Dillon led the two to amicably divorce.

Erica and Jack got back together once again following her release from prison where she spent a few months for kidnapping Maria and Edmund's baby. The two bonded while trying to cope with Bianca's anorexia, and were quickly engaged. This engagement hit a roadblock when Erica's presumed dead lover Mike Roy came back to town. After months of complications, Jack finally told Erica she had to make a choice between Mike or himself. Erica chose Jack, but spent one final night with Mike as a way of saying goodbye. Jack walked in on the two in bed and called things off with Erica, not caring that she had ultimately chosen him.

Shortly after, Jack learned that his sister Christine did not die in a boating accident as a child - an accident he had blamed himself for. Under the name Kit Fisher, Jack's sister came to town and accused Ryan Lavery of rape. Once Jack found out Kit was his sister, he ruthlessly went after wrongly accused Ryan, who was later proven innocent.

Jack was dealt a crushing blow a few months later when his brother Travis died of a massive stroke. Jack took on a paternal role in Bianca's life after she came to live in Pine Valley, and was incredibly supportive during her coming out process.

While Jack worried over his daughter Lily's brief illness last year, Erica comforted him and the two made love. Erica was engaged to Chris Stamp, but the undeniable feelings between Jack and Erica had been reignited. Jack accused Erica of sleeping with him because she didn't really want to marry Chris, and vowed to fight for her. Despite Erica's protestations, it was clear she cared for Jack. Chris eventually found out about their night together and broke his engagement with Erica. A jealous Chris hired a thug named Flanders to trail Jack and possibly cause some trouble for him. Flanders took Chris's instructions a few steps further and attempted to kill Jack. While recovering from a gunshot wound, Erica declared her love for Jack and the two officially reunited.

Jack was rushed to the hospital with internal bleeding, and needed a blood transfusion to save his life. Erica learned that Greenlee du Pres donated the blood that saved Jack's life, and quickly pieced together that she was Jack's biological daughter (from a long ago affair with Mary Smythe). Erica kept this information from Jack as the two got engaged and planned their wedding. Just as they were about to say their vows, Greenlee interrupted and revealed herself as Jack's daughter. Disgusted that Erica lied to him, Jack broke it off with her.

Jack had taken in Trey Kenyon's ward, Reggie Porter, after Trey was sent to jail. Reggie and Jack bonded and quickly developed a father-son relationship, which Jack made official when he formally adopted Reggie.

Jack attempted to put Michael Cambias away for Bianca's rape, but was unsuccessful due to lack of physical evidence. Jack swore revenge on Michael, and planted heroin in his condo in hopes of sending him to jail. Michael was soon found dead and Bianca's sister Kendall accused of the crime. Jack devoted his energies into helping her in any way he could, including admitting on the stand that he had planted the heroin in Michael's condo!

While building a relationship with Greenlee, Jack slowly grew closer to Erica. However, Erica's need to keep up the charade of a romance with David Hayward publicly, in order to keep an alibi, caused significant problems. Still, Jack and Erica found their way back to each other and were engaged again.

Jack learned that Bianca never terminated her pregnancy from Michael's rape. Knowing Bianca kept this secret for fear of Erica's reaction (Erica had been raped and impregnated at 14), Jack agreed to keep her secret. After Erica learned the truth about the pregnancy and that Jack had kept this knowledge from her, she distanced herself from him. Concerned, Jack observed that Erica had begun drinking (she had been addicted to pain killers years earlier and hadn't consumed alcohol in years). Jack attempted to get Erica to open up to him and admit her feelings of betrayal, but Erica remained emotionally closed off.

Jack was devastated when Bianca's baby, Miranda, died shortly after birth. Unknown to Jack, Miranda was still alive and was believed to be Bess Chandler, Babe Chandler's daughter, thanks to an elaborate scheme by the villainous Paul Cramer. Erica, reeling off the death of Miranda and her father, left Pine Valley for parts unknown. Jack managed to track her to Las Vegas where she was self-medicating with alcohol. Despite his attempts to support her, Jack realized that Erica did not want to be helped. Eventually, Erica returned to Pine Valley where he and Erica's loved ones staged an intervention. Erica agreed to seek treatment for her alcohol abuse and Jack promised to support her. When Erica returned, she and Jack slowly bridged the distance between them. Erica proposed and Jack accepted.

Bianca slipped into a coma following a fall from a balcony. Erica and Jack learned that Bess Chandler was really Miranda, and they worked to get a DNA test to prove it. A test was authorized, the results obtained and Erica urged Bianca to come out of her coma and be a mother to Miranda. Bianca woke up and Jack was overjoyed to see mother and daughter reunite.

Jack learned that Greenlee had been consistently and systematically drugged with anti-psychotic medication, leading to his daughter to have a break with reality. Greenlee recovered, but Jack is determined to find the person behind Greenlee's poisoning.