Actor Tyler Christopher originated the role in 1996 and portrayed him, on and off, until 2016. Christopher brought home his first Daytime Emmy for Outstanding Lead Actor in 2016. He has been portrayed by Marcus Coloma since 2019.
The role of Emily, originated by Amber Tamblyn from 1995 to 2001, was played by Natalia Livingston from 2003 to 2007, with recurring appearances in 2008 and 2009 and guest appearances in 2013 and 2014.
Emily was strangled to death by Diego Alcazar on November 14, 2007.
Nikolas was presumably shot and killed by Valentin Cassadine on July 19, 2016. He was revealed as alive on October 31, 2019.
Nikolas and Emily met as teens and were apart of General Hospital's teen scene of the late 90s, along with Lucky Spencer and Elizabeth Webber. The four were known as the Four Musketeers and were involved in several mysteries and adventures around Port Charles. Nikolas and Emily were best friends, and as they got closer Emily began to develop romantic feelings for him. However, she didn't feel that Nikolas returned her feelings at that time, so she started to date Juan Santiago instead.
Emily left town in 2001 and returned in 2003, hiding the fact that she had developed breast cancer. She reconnects with Nikolas, and convinces him to fake a romantic relationship with her, so she can hide her diagnosis from her ex-boyfriend, Zander Smith. Nikolas agreed because his uncle, Stefan Cassadine, had been pressuring him to marry Lydia Karenin, a wealthy heiress who can save his family from losing their fortune, and he was looking for a way out of the marriage.
Emily and Nikolas became engaged, despite protests from Stefan and Zander. On the night of their engagement party, a hitman hired by Stefan accidentally throws Summer Holloway, Lucky's girlfriend, over a cliff to her death in an attempt to murder Emily. As Emily battled breast cancer, Nikolas became her most trusted confidant. As their feelings grew, Emily became torn between Nikolas and her first love Zander.
Nikolas develops true romantic feelings for Emily, but Emily decides to tell Zander the truth. Zander and Emily reunite and she begins an aggressive chemotherapy treatment. Nikolas marries Lydia, but Emily discovers he is in love with her after overhearing a conversation between Nikolas and his wife. Emily and Nikolas confess their feelings for each other, but decide not to act on them because of her illness, Zander and Lydia.
Emily is forced to stop chemotherapy because it was destroying her immune system. She soon develops meningitis and believing she would die, she married Zander as her last gift to him. Shortly after, she lapses into unconsciousness and dreams of kissing Nikolas, who happens to be in the room next door. Buoyed by her dream, Emily eventually enters remission and fights her attraction to Nikolas. Attempting to make her marriage work, Emily moves into Brenda Barrett's old cottage with Zander. However, Emily and Nikolas could no longer resist each other and slept with one another on the floor of the cottage Zander bought for her. Witnessing their adultery started Zander on a downward spiral, and Emily ended their marriage.
Nikolas divorces Lydia shortly after he proposes to Emily. Nikolas' aunt, Alexis Davis attempts to sell their family home, Wyndemere, but Emily buys it for Nikolas. Nikolas and Emily hold an auction at the Port Charles Hotel to sell some Cassadine family treasures, when the entire hotel catches on fire. Nikolas gives his seat to Emily on the last helicopter evacuating guests, and is later presumed dead, but returns to find Emily recovering in the hospital.
Zander, who lost his father in the hotel fire, became increasingly unstable. He took Emily hostage and tried to kidnap her, but he later lets her go and is gunned down by the police. He dies in Emily's arms. Nikolas was driving home from buying Emily an engagement ring when he heard of the hostage situation. It caused him to get into a car accident that leads everyone to believe he is dead. However, in reality, war widow, Mary Bishop took him in and left Port Charles, leaving Emily and his family to believe he was dead. Mary's husband, Connor Bishop, who looked identical to Nikolas, had been presumed dead in the Iraq War. Mary lied to Nikolas and convinced him that he was her late husband, Connor.
Emily convinces Lucky to go on a trip to Mexico that Nikolas had planned for them, and is stunned when she spots Nikolas, who was there with Mary to renew the vows she had made with Connor. Deciding not to force Nikolas' memory to return, Emily confronts Mary back in Port Charles, but decides to keep the truth from Nikolas, remembering the trauma her brother Jason Morgan endured because of his memory loss. When a still amnesiac Nikolas learns that his friends and family knew who he really was and didn't tell him, he rejects them in favor of a life with Mary.
Lucky, who had been Emily's support through this ordeal, admits he has romantic feelings for her, but she gently rebuffs his advances. While Emily decides to become a doctor like her parents, she also carefully worked to unlock Nikolas' fragile mind, and when Nikolas finally remembers Emily, the two reconcile. A distraught Mary goes insane and murdered Sage Alcazar and another teen before she is shot and killed by Nikolas. Nikolas and Emily get engaged again. Unhappy with the news, Nikolas' grandmother, Helena Cassadine attempts to murder Emily, but Nikolas stops her by throwing Helena over a cliff.
Shortly after Mary's death, her husband, Connor Bishop, who had gone AWOL and faked his death, came to town on orders from a very alive Helena. His task was to kidnap Emily, which he does. After a confrontation and struggle with Nikolas, Connor is shot. Nikolas, Lucky, Elizabeth, and Emily debate about turning Connor in for being AWOL, but agree to help him escape to Canada. When Connor foils their plans, to spare Emily the pain of a trial, Nikolas pled guilty to Helena's murder, and the two married before he was sent to prison.
Connor returned to town again with orders from Helena to seduce Emily. Believing Helena is alive, Emily convinces Connor to pretend he is Nikolas, as she instructs him on the finer arts of being a prince. Connor becomes obsessed with Emily, and rapes her. After, Emily manages to kill Connor. Elizabeth and Lucky arrive, and while Lucky buries Connor, Elizabeth tries to get Emily to admit Connor raped her. Emily's attack caused her to emotionally pull away from Nikolas.
Helena resurfaces, kidnaps Emily, and shoots Lucky, who tries to save Emily. Lucky falls into a coma, and Emily confesses that she was raped to her first friend. When Lucky recovers, he moves into Wyndemere with Emily, and attempts to help her recover from the rape. In prison, Nikolas becomes concerned about Emily's reluctance to touch him, and she admits Connor raped her. Helena is captured, though Nikolas is devastated that Emily cannot be with him because he looks just like her rapist. Helena's capture led to Nikolas' release from prison.
Emily tried to make her marriage work, but she was unable to connect with Nikolas and this put a strain on their marriage. Nikolas' befriended Courtney Matthews, who was in her own strained marriage to Jasper Jacks. Nikolas and Courtney soon embarked on an affair. Eventually the truth of the affair came out and Jax ended his marriage to Courtney. Emily and Nikolas divorced as well. Soon after Courtney became pregnant and it was unclear if the father was Nikolas or Jax.When Jax learned that Nikolas was the father, he switched the results of a DNA test in order to protect Courtney and the baby from Helena. When Sonny Corinthos learned that Nikolas was having an affair with his sister, Courtney, he offered Emily a place to stay, because she is Jason's sister. Jason was out of town with his girlfriend, Sam and unable to help Emily at the time, so Sonny offered and Emily decided to stay at his place. While staying with Sonny, Emily became a nanny to his boys, Morgan and her nephew, Michael.
Emily begins a romantic relationship with Sonny, but resumes her friendship with Nikolas. Nikolas and Emily share a close moment, that a pregnant Courtney witnesses. She misinterprets the moment between them and leaves town. She is briefly abducted by Helena but escapes. After her escape, she returns to Port Charles in the middle of an encephalitis outbreak, and she and Nikolas both become ill.
Because of her illness, a C-section was necessary to save the baby, which lead to her death. Jax still claimed to be the father but within months, Robin Scorpio-Drake revealed the truth to Nikolas at the baby's baptism. Nikolas renamed his son, Spencer Cassadine to honor Lucky and Lulu, and when Spencer was re-christened, Nikolas chose Emily to be his godmother. When Helena returns to town attempting to kidnap Spencer, Nikolas and Emily stop him together. Emily even allowed herself to be taken hostage by Helena in order to save Spencer.
Overtime Nikolas and Emily grow closer, their friendship rekindling and getting stronger. Emily ends her romance with Sonny and focuses on being there for Nikolas and Spencer. In early 2007, Nikolas and Emily decide to rekindle their romance. They attend a fundraiser at the Metro Court Hotel and became trapped inside together when a group of mercenaries, led by a plastic surgery disguised Jerry Jacks, took over the Metro Court to find a package that Lorenzo Alcazar left in the hotel's security vault.
Nikolas and Emily both helped care for an injured Robin after she is shot by Jerry, and Nikolas supported Emily when her father Alan Quartermaine died, as the result of a heart attack he suffered at the incident's conclusion. A few months after the Metro Court crisis, Jerry, using the alias James Craig, injects Nikolas with an experimental poison in a bid to have Nikolas finance a new life for him with the Cassadine fortune. Robin discovered Jerry with Nikolas, and Jerry forced her to pretend she was involved with Nikolas. This also forced Nikolas to end his relationship with Emily.
Emily eventually learned the truth about Jerry's blackmail and worked with Robin, Elizabeth and Dr. Patrick Drake to develop an antidote that would save Nikolas' life. After this ordeal, Nikolas and Emily resume a romantic relationship. Nikolas goes on to experiences periods of rage where he begins to blackout. He discovers that he has beaten Logan Hayes and stabbed Jerry, while several other women in town are strangled to death by the Text Message Killer.
Emily convinces Nikolas to have tests performed, but he insists on throwing a ball first to honor their renewed love. Dubbing it the Black and White Ball, he invites all of their friends to come and celebrate he and Emily. The night of the ball, Nikolas proposes to Emily, and she accepts. The celebration took a turn for the worse, when maniacal mob boss, Anthony Zacchara bulldozed his way into the ball and began terrorizing guests. Tragically later that night, Emily was strangled to death by the Text Message Killer, who had also infiltrated the ball to terrorize guests. Nikolas was devastated by Emily's death and Elizabeth had to pull him away from her body.
Nikolas' grief for Emily went on for months. He had a hard time letting go of Emily and due to the tumor in his brain, he started to see Emily in visions. When his loved ones tried to get him to have surgery to remove the tumor, he refused, not wanting it removed because it allowed him to see Emily. He also hoped that his hallucinations would help lead him to the identity of Emily's killer.
Nikolas soon discovers that Lorenzo's presumed dead son, Diego Alcazar is the Text Message Killer. Nikolas hunted Diego down and confronted him. The two got into a fight and Diego is inadvertently killed when chains become wrapped around his neck. Dr. Ian Devlin tells Nikolas he has an experimental drug that will allow him more time with his visions of Emily, and Nikolas agrees to pay him ten million dollars. He also starts a program to allow patients without insurance to be treated at General Hospital, much to the pleasure of Emily's mother. Dr. Monica Quartermaine.
Convinced that Emily would want this and for the sake of his son, Nikolas finally decides to go forward with the surgery that will remove his tumor and his visions of Emily. Emily visits one last time, leaving her engagement ring in his hand. They share a poignant goodbye while he is undergoing surgery. Nikolas awakes with her engagement ring in his hand, the surgery a success. He later establishes a clinic in Emily's honor, naming it the Emily Bowen-Quartermaine Memorial Clinic.
Nikolas proposed to Emily on September 13, 2004 and October 31, 2007.
Nikolas and Emily were married at Wyndemere on December 2, 2004.