Of the role, Egan has stated during a 2012 interview with On-Air On-Soaps:
She divorces her ex-husband, Terry McDermott, when she learns that he has a penchant for seducing young teenage virgin girls. Fearing what Terry will do to their daughter, Emma, when she reaches puberty, Annie sues for custody, but loses thanks to Terry's impeccable record. Desperate, Annie kidnaps Emma and takes her on the run. With help from Erin Lavery and Jamal Cudahy, Annie hides out from Terry and the authorities until September 2006 when Terry is killed by Jonathan Lavery. Prior to Terry's death, Annie mistook Jonathan's brother, Ryan, for Terry and shot him. Ryan survived the shooting.
Annie's ex-husband, Terry, as it turns out, is not Emma's biological father because Annie had been artificially inseminated (a DNA test had been done during her divorce from Terry and custody proceedings showed that Annie is not Emma's biological parent either). David Hayward tells Dixie Cooney that he has run a DNA test on Emma, and, lying to Dixie (in order to get her hopes up and to see him as a savior), finds out that Emma is actually Tad Martin and Dixie's lost daughter, Kate. Annie becomes angry at Dixie's belief that Emma is Kate, but refuses to take a DNA test because she already knows the results of the earlier DNA test done during her divorce from Terry, but does not tell anyone else of this. She later relents and another DNA test is done (without David's involvement, and which uses samples from Tad, Dixie, and Annie), which proves that Emma is not Kate. Relieved at the result, Annie then learns from Ryan Lavery (who has become her friend) that she may possess a DNA condition called chimera, which means that she has two sets of DNA. More DNA tests are run at various labs. Finally, one lab proves that Annie is actually the biological mother of Emma. In the process, Ryan and Annie become closer and go out on their first date. Annie confides to Kendall Hart that she is falling in love with Ryan. Kendall is somewhat perturbed, because, before leaving, David tells her that Emma is actually Ryan's daughter as well. Kendall then sees Annie as a rival for Ryan's affections, even though Kendall is married to Zach Slater and has a son, Spike (conceived through artificial insemination with Ryan as well). Kendall asks her half-brother, Josh Madden, to run a DNA test to see if Ryan truly is Emma's biological father.
On December 28, 2006, Kendall learns that Ryan is indeed Emma's biological father, and faces a choice on whether or not to tell Ryan. Ryan, however, discovers that he is Emma's biological father, when he and Josh Madden drug Zach with truth serum. Ryan hesitates to tell Annie that he is the father of her daughter, but finally tells her the truth. He and Annie soon become closer.
Annie and Ryan consummate their relationship, and begin dating. She helps care for Spike while his mother, Kendall, is being stalked by the Satin Slayer, a serial killer. Ryan proposes marriage to Annie, and after some thinking, Annie gladly accepts.
On May 10, 2007, Ryan and Annie are married, but their reception is soon brought to a halt by the police, who arrest Ryan on charges of bigamy. Unknowingly, he had wed Annie when he was still technically married to his estranged wife, Greenlee Smythe. But Annie has her own secret — one that if she tells anyone, she fears that she will be as hated as Greenlee is.
On August 15, 2007, Annie visits her estranged father, Walter, for help with Spike. He sends Annie to her mother's grave. When she gets to her mother's grave, she breaks down in tears, telling her mother that she is sorry. Annie later reveals her secret to Ryan — that she had her brother, Richie Novak, sent to prison in order to protect her family. Her parents would not believe her that he was a danger, and she had to act fast. This act of having Richie imprisoned is what caused the rift between her and her father. It is not long after telling Ryan this secret, that Annie hears of her brother being in town and that he has held up Babe Carey and a new guy in town named Wes at a bar called The Comeback. When "Richie" later turns up dead, and Annie has to identify the body, she informs all in the room with her that he is not Richie; that the dead man before her is not her brother. After seeing that the man has a fresh tattoo on his neck identical to that of the signature tattoo in which Annie described her brother having, and he stayed only three cells down from the real Richie while in prison, Chief of Police Derek Frye comes to the conclusion that the real Richie Novak had a man imitate his appearance in order to taunt Annie. Ryan decides to get Annie out of Pine Valley for her own safety, fearing that her brother is out for revenge against her. They leave Emma in Zach and Kendall's care. While away, Ryan fiddles with a computer-generated image of Richie; the image depicts Richie with long hair and a beard. Ryan slowly chips away at the hair and the beard. By the time that he is done, Annie has appeared at his side and exclaims, "Oh, my God... That's Richie. That's my brother." Once back in town, the two do all they can to battle Richie and his schemes, which one after another are targeted at Annie.
Ryan loses memory of the last four years of his life and can't remember Annie or Emma or Spike. He thinks he loves Kendall and reconnects with Greenlee, making Annie jealous and wanting to regain his love. She suffers a fall and tells him that someone broke into her house. She does this because he is closest with her when crisis occurred. He then remembered parts of his past with her. Insecure, she asks Richie to get rid of Greenlee; instead, Richie briefly kidnaps his obsession, Babe. Annie murders Richie by striking him in the head with a tire iron because of all the pain he has inflicted.
In an effort to cover this up, she tells police chief Jesse Hubbard that Zach Slater wanted to kill Richie. Further conflict arises between her and Kendall and Greelee, who she feels is trying to take her away from Ryan. She is taken to hospital after Zach stressed her with questions about Richie's death; she finds out that she is pregnant and Ryan never had a vasectomy. Annie overhears Colby Chandler, Cassandra Foster, Dre Woods, and Peter Cortlandt talking about running over Richie. She begins plotting to frame them for murder. She finds out that Ryan loves Greenlee, causing her to get a restraining order against him and tries to kill Greenlee; but miscarries her baby in the process.
Zach finds out that Annie killed Richie. It is then revealed to all, and she gives Ryan full custody and she gets psychiatric help. Along with Aidan Devane, she plans the kidnapping of Emma to get their spouses back. She has Aidan take her away so that she can work on her marriage to Ryan. Di finds out that Annie had reported Emma missing. He threatens her with a gun and the two struggling, resulting in Di being wounded. Emma is saved from a burning church. When they returned home, Ryan told Annie he knew she was behind the kidnapping. Annie threatens him with a gun, only to be threatened back by Greenlee, who the gun is given to. She jumps from the balcony. She then appears at Wildwin having delusions about celebrating Thanksgiving dinner with the family. She is then seen at ConFusion, dressed up in a blood spotted wedding dress for all Pine Valley residents to see. She thinks she is marrying Ryan again and is holding a bloody knife. Ryan asks Annie who she hurt and the camera flashes to Erica. She is committed to Oak Haven. She believes herself to be Emma and escapes from Oak Haven and returns to Ryan's home. She is still sick and picks up a weapon to attack Greenlee. Ryan intervenes and he is knocked out. She is then taken back to Oak Haven by Jesse and police officers.
As time goes on, Aidan takes notice of Annie's psychiatrist's, Dr. Sinclair, suspicious behavior. She seems determined to see Annie locked up for her crimes. Soon, Ryan realizes this and has Tad dig up information on her past. It turns out she was Richie's psychiatrist in prison for a time period and had developed a romantic relationship with him, this being the reason she was terminated. After finding out Annie murdered the love of her life, Dr. Sinclair becomes hellbent on revenge. She even tries to manipulate Annie into confessing to Richie's murder. However, once her true intentions are revealed and she realizes she has blown her cover, a desperate Dr. Sinclair attacks Annie with a syringe filled with poison. Aidan comes to Annie's rescue and Sinclair herself gets stabbed with the needle instead, and is taken into custody. Dr. Sinclair confesses to everything, exonerating Annie. Annie is grateful for Aidan's act of nobility.
Once Annie finds out that Ryan and Greenlee are getting married in Connecticut, a hurt Annie escapes Oak Haven and follows them. There, she confronts Ryan with a gun, determined to hold on to him. However, Aidan shows up and convinces Annie to put the gun down and to finally let go of Ryan. He tells her if she comes back to Oak Haven, he will continue to help her through her recovery. Annie makes some progress in her mental recovery, thanks to Aidan. As she and Aidan grow closer, it comes clear to Aidan that he has romantic feelings for Annie, but it is uncertain on how Annie feels. Annie and Aidan end up being together, despite Annie being a mental patient. Annie now has a new doctor named Dr. Burke. Annie has been seeing a girl, named Tori come into her room, and talk to her. Aidan cannot see her, so he begins to worry about Annie. Tori talks to Annie about birthday parties, and Richie, and other things, things about Annie. Annie has been having nightmares about her 7th birthday party, and Aidan is becoming more worried. Aidan does some digging into Annie's past, and finds that a little girl, named Tori, was murdered by Richie. Annie also figures this out, and has made an amazing breakthrough. Upon being transported to a new psychiatric facility, with the help of Aidan, Annie escapes. With a fake ID and passport, she and Aidan plan on leaving the country. However, Ryan happens upon them at a motel and manages to catch Aidan, while Annie gets away. For a certain amount of time, Annie hides in the Maldives. Unable to live without her daughter, she returns to Pine Valley, with no one, not even Aidan, knowing of her return.
On the night that everyone in town is gunning for Adam Chandler at his mansion, Annie is also there after discovering that Emma is spending the night there. With a gun in hand, she shows up at the Chandler mansion, looking for Emma, at the time that Stuart Chandler, Adam's twin, is mistakenly shot. It is soon discovered that, after finding Emma, Annie ran into Adam, who was delirious and very ill, and took him up to the attic, where she helped him get better. Then she turned herself in.
While in prison, Annie is stabbed by a fellow inmate. She is rushed to Pine Valley Hospital where Adam, having remembered bits and pieces of that night, finds her and offers to help her, in exchange for saving his life. Seeing this as an opportunity to fight all the charges against her and see her daughter again, she agrees and lets go of Aidan. She goes to court and Adam offers for her to live with him. The judge agrees and she moves in under house arrest.
After Adam and Annie get engaged, Annie learns that she is free of her house arrest. Annie and Adam are married before Adam collapses from seeing his brother. This is discovered, by Dr. Jake Martin, that Annie is pregnant with Adam's child. However, on November 20, she loses the child after Adam finds out about her and Scott's kisses. But, as Erica informs Adam, "that is not all." Annie goes into a coma and later wakes up and is arrested because Adam confessed to the murder. Annie decides to represent herself in court after she fires Liza Colby as her attorney and begins to have doubts in Adam's love. During her court case, Annie questions herself on the stand and Adam admits to killing and covering up the murder of his brother. Since he was already found innocent, the charges against Annie are dropped and Adam is protected under double jeopardy. Annie crashes the (Hayward/Smythe) now non-wedding and is stunned to see Greenlee. She tells Adam and swears that seeing her archenemy does not evoke any old angers or insecurities, but we see she may be lying.
Annie strayed from her marriage by cheating with her JR during a trip to Washington DC. They had an affair, and Adam found out. He had a divorce and threw her out of his life. He left town, leaving Annie heartbroken. She later romanced Scott Chandler, who she asked to marry her to avoid her temptations where JR is concerned. Scott later proposed himself and they married, before she found out that he had sex with Marissa. While on honeymoon, they discovered that David Hayward was murdered and returned to Pine Valley. Annie cheated on Scott by sleeping with JR again. Scott was later arrested and sent to prison for stealing the Nanotech project from Palmar Cortlandt, and they divorced. She later saw her daughter and admitted her love for JR.
Paranoid about JR and Marissa's relationship, she followed her to the Chandler Mansion and knocks her out with a door accidentally; she convinced everyone it was a burglary. Colby finds out the truth, resulting in Annie handcuffing her to a table at the cottage. She is fried, and JR wants to take Annie to rehab. She began having delusions and became mentally ill. Her delusions caused her to accidentally run the ambulance carrying a critically ill Kendall off the road. She kidnaps Ryan and Greenlee's wedding and kidnaps Emma, whom she takes on the run. Ryan finds Annie and JR convinces her to go back to the mental hospital. It is discovered later on that during the trip Annie constantly said bad things about Greenlee during their time on the run to get Emma to turn against her. Annie returned in July 2011 with Janet Dillon, Marian Chandler, Dixie Cooney, and Erica Kane in scenes at Oak Haven. She returned for the series finale.