Philip entered the world in an unusual way. Unable to get pregnant, Kate went to the doctor's office to be implanted with Victor's sperm. The fertilized egg ended up in Vivian instead, and Vivian actually carried Philip to term, trying to get Victor for herself. Not long after, Philip was in high school, and was hanging out with fellow rich brats Jan Spears and Jason Welles. The three made a point of torturing new girl Chloe Lane, until Philip got a chance to see a different side of Chloe, and fell in love. The relationship hit a snag when she falsely accused him of rape, and another snag when he dumped her after nude photos of her appeared at the Last Blast dance.
Philip was never able to get things going with Chloe again, and when he realized that she had found new love with Brady Black, he left Salem to join the military. He wasn't gone long though; he returned to town as part of the Love Is Blind contest -- he was the mystery hunk -- and re-developed a crush on his good friend Belle Brady. Philip was more than just Shawn and Belle's high school chum though. In addition to being a dedicated military cadet, he was also secretly working for the ISA. He and Tek, a newcomer to town, worked hard to prove that Tony DiMera was involved in some nefarious dealings around town. Not only that, but Philip let his mother bully him into spending more time with Belle, whom by this point he was hopelessly in love with.
Philip and Belle got engaged, with Philip thrilled that he and Belle were going to be able to live their lives together. Unfortunately, just as they were getting engaged, Philip was being called to active duty in Iraq. The two moved up their wedding plans, getting married immediately before Philip had to ship out. Philip returned home, but he had lost the lower part of his leg in connection to a Tony DiMera plot. He was thrilled to learn of Belle's pregnancy. Claire Kiriakis was born at St. Luke's on what was supposed to have been her maternal half-aunt Sami's wedding to her paternal half-uncle Lucas. Unfortunately, the wedding never happened.
Philip, Belle and the baby were transported to the hospital, and it was there that Belle and Philip chose their daughter's name -- it was a mutual favorite -- and Shawn and Mimi consented to be the child's godparents. When baby Claire became ill, Kate learned that her blood type was AB- and after talking to a medical student realized that there was no way Philip could be Claire's father, and soon realized that it must be Shawn. Unfortunately for poor Claire, her health continued to deteriorate, and it wasn't long before Lexie Carver realized that if Claire didn't get a liver transplant, she wouldn't survive. Luckily for Claire, Zack Brady was a match, and she received his liver after he died.
Claire recovered, and her parents were thrilled, but when the truth finally emerged about her paternity, thanks to Chelsea's intervention, Philip left town for a number of weeks, and Shawn tried to adjust to being Claire's father. Belle didn't want him near her initially, especially after learning of his relationship with Willow, a former prostitute. Belle and Shawn finally began to reach an agreement about Claire when she was kidnapped from a diner. This terrified both Belle and Shawn, who then fell under scrutiny from social services. Unbeknownst to anyone, on the occasions when Belle would allow Victor to visit with Claire, she was also spending time with Philip, who had been injured in his duties as a Marine and needed reconstructive surgery.
When the case finally went to court, Philip showed up, having just had a face transplant, and won temporary custody of Claire, who was legally his daughter because he was married to Belle at the time of her birth and was named as her father on the birth certificate. Shortly after, Shawn and Belle kidnapped the little girl and fled the country, with Philip desperate to find out what had happened to the child he'd raised for the first year of her life. Philip was willing to use any methods to get Claire back, including teaming up with E.J. Wells.
Philip began his attempts to win Belle back, but she still maintained her relationship with Shawn. Belle and Philip even became lovers again after her father, John, died, but Belle chose to marry Shawn. When Shawn messed up at a crime scene, Philip offered to do anything he could to help Shawn with his career -- if Belle would sleep with him. Belle agreed to do so, but at the last moment, Philip felt guilty and told her she didn't have to go through with it. Shawn, Belle, and Claire left Salem soon after to bond as a family.
When Shawn, Belle, and Claire left Salem, Philip threw himself into work. Victor appointed Philip as CEO of Titan, where Philip worked closely with Titan shipping. Philip went head-to-head with John Black DiMera over the shipping ports in Salem. Philip told the authorities that John Black DiMera had paid off a customs official, Paul Hollingsworth, to unnecessarily detain Kiriakis ships, allowing DiMera ships through first. When no charges were leveled against Hollingsworth, thanks to some help from John, Philip paid Paul to plant massive amounts of drugs on John's ships. The feud continued until Paul went "missing." John and Philip were both suspects in Paul's disappearance.
Unaware of Philip's dealings with Paul, Morgan Hollingsworth, Paul's daughter, began a friendship with Philip. Philip used Morgan to keep an eye on her father's search, but eventually, he developed feelings for her. He broke off a brief fling with Chloe to focus on Morgan. But just as they were about to get close, Morgan learned of Philip's relationship with her father. She broke things off with him and moved to Chicago.
Philip threw himself into work and family. He continued to run Titan and told Nick Fallon that Titan would be glad to purchase the rights to the alternative fuel project as soon as some of the kinks were eliminated. He hired Stephanie Johnson as an intern and hired Melanie Layton as an executive assistant.
While work was going well, Philip got bad news in his family. Kate had stage four lung cancer. During her illness, Philip leaned on Stephanie for support. The two grew closer and began dating, much to the dismay of Melanie, who had feelings for Philip. Melanie tried to get between Stephanie and Philip on several occasions. Fed up with her, he fired her from Titan and told her that Titan had no interest in the alternative fuel project that she had become the sole owner of.
Furious and hurt, Melanie told Victor about Philip passing on the project. Victor confronted Philip and warned him not to let emotions get in the way of business decisions. Philip agreed. To make sure that Philip did not get out of line, Victor appointed Brady as vice CEO. Philip felt blindsided by Brady's hiring and competed with him for Victor's attention.
Philip attempted to get Victor's attention when he bought the rights to Melanie Layton's alternative fuels project for Titan. But when Philip refused to have a romantic relationship with Melanie, because Philip was dating Stephanie Johnson, Melanie sold the project to DiMera Enterprises. When E.J. revealed that he had bought the project just to stop the fuel source from ever being developed, Melanie sold the project to Tony DiMera. Furious that Melanie had taken the fuels project from Titan, Philip confronted Tony DiMera. As Tony was walking away from Philip, Tony slipped and fell. Tony died from complications from the fall. E.J. and Stefano blamed Philip for Tony's death.
Victor blamed Philip for losing the project. But their problems got worse when a full-blown feud erupted between the DiMera and Kiriakis families. Stefano and E.J. ordered two hits on Philip. First, a hit man was hired to shoot Philip. When Philip survived, the DiMeras paid a nurse to drug Philip. However, Hope broke into Philip's hospital room and stopped the nurse before Philip died. In retaliation for the hits, Victor and Philip arranged for Stefano to be kidnapped, and they held him hostage, denying Stefano the proper amounts of insulin. Victor demanded that E.J. sign over the rights to DiMera Enterprises in return for Stefano.
Rather than sign over the rights, E.J. had Stephanie Johnson, Philip's fiancée, kidnapped. Philip agreed to swap Stefano for Stephanie with E.J. But the man that E.J. had hired to kidnap Stephanie had other ideas. Owen wanted to keep Stephanie for himself. Owen stored her in the Heritage Park Mortuary. Melanie, Brady, and Philip tracked Owen down. Pretending to be a corpse, Philip sneaked into the morgue and rescued Stephanie.
But the experience took a toll on Stephanie. She blamed Victor and Titan's dirty business for her kidnapping and asked Philip to leave his family business before they married. Philip agreed, but couldn't bring himself to cut off all ties with his father. So, Stephanie broke off her engagement to Philip.
Determined to find a girl that would accept his family, Philip set his sights on Melanie. Despite the fact that she was dating Nathan Horton, Philip pursued Mel. He proposed to her on Christmas Eve 2009. The two were married on Valentines Day of 2010. Yet, Melanie still had eyes for Nathan.
When Nathan confessed that he returned Melanie's feelings, the two shared a kiss. Philip walked in on the kiss and was furious. A drunken Philip sought comfort from Chloe. Philip and Chloe slept together. Melanie ended up confessing everything about the kiss to Philip, explained that she was sure that she had married the right man, and asked Philip to forgive her. Philip agreed but was guilt-ridden about his night with Chloe. To make matters worse, Chloe found out that she was pregnant.
A paternity test confirmed that Philip was the father of Chloe's baby. Yet, someone changed the results of the test before Chloe could see the original results. Chloe believed that Daniel was the father of her baby and proceeded to plan a happy life together with Daniel. Philip was relieved and looked forward to a future with Melanie. Chloe gave birth to a baby boy, Parker.
On the day of Parker's baptism, Caroline Brady revealed that she had switched the test results. Philip was Parker's father. Melanie was heartbroken and left Philip. But, she soon learned that she was also pregnant with Philip's child. Philip hoped that the baby would bring Melanie back to him. Melanie had almost agreed, but then Melanie suffered a miscarriage. The trauma made Melanie reevaluate her life. She realized that although she still loved Philip, she couldn't be with him and be a mother to Parker. Melanie filed for divorce.
Philip turned his attention to Chloe, as she was having some bad problems with depression after Daniel left her. Philip even rescued Chloe after she tried to commit suicide by jumping in the Salem river. After her suicide attempt, Chloe signed full custody of Parker over to Philip in order to avoid having child services put Parker in a foster home. Chloe continued to decline and during a drunken rant to Kate, threatened to take Parker and no one would ever see him again. Fearful that she would make good on her threats, Philip took Parker and moved to Chicago. He calls often to talk to Kate and Victor. Philip is still in town occasionally on business, but not shown on screen.