Chrissie believes she is the daughter of Chief Executive Officer Mark Williams, and former staff nurse Tricia Williams, although unbeknownst to her, she is actually the biological daughter of Frank Williams, Mark Williams' father, who raped her mother. Upon her arrival at Holby City Hospital, Chrissie clashed with several of her colleagues, including Sandy Harper and Jasmine Hopkins. Chrissie expected a high standard and made it clear that she would tolerate nothing less - reprimanding Sandy harshly for occasionally being a few minutes late for her shifts.
Time at Holby City Hospital
Early in series four, Chrissie began an affair with married Cardiothoracic Consultant Alistair Taylor. He soon became besotted with her and ignored Chrissie's repeated attempts to rebuke him. Chrissie attempted to sever relations between them and was saved by Obstetrics Consultant Owen Davies when Alistair attempted to restrain her physically. Chrissie's relationship with Owen developed alongside her affair with Alistair. Owen and Chrissie had known each other for a while and had a brief affair, which almost ended Owen's marriage. Almost as soon as she ended her affair with Alistair, she started flirting with Owen again and tried to lure him away from his wife. Owen initially resisted but soon gave in and they slept together but were caught by Owen's daughter, Katie. Katie told her mother what she had seen and Laura threw Owen out but she struggled to get on with Katie, and resisted making any commitment to Owen - although she did agree to move in with him. They got engaged in series five but despite this, Chrissie had an affair with Cardiothoracic Registrar Ed Keating. When she discovered that she was pregnant, she wasn't sure who the father was. This was accidentally revealed to Owen by his colleague, Mubbs Hussein, and he ended their relationship. Chrissie stayed with Lisa Fox, before moving in with her mother, Tricia, who had recently returned from Spain. Unfortunately Chrissie went into premature labour and Owen had to deliver the baby by caesarean section but she was born with brain damage so Chrissie only had a few minutes with her before she died. Owen ordered a paternity test after the birth but threw the results away without looking at them. Chrissie later told Owen that she wanted a divorce so Owen began an affair with her mother, Tricia. Although Owen and Chrissie briefly reunited in early series six, Chrissie ended the relationship again when she discovered his affair with her mother and had a one night stand with Mubbs.
Chrissie's relationship with her mother was, for a long time, marred by her affair with Owen. After taking a refresher course, Tricia began working as a nurse at the hospital but it took Chrissie a long time to forgive her. When she discovered Tricia had breast cancer, Chrissie went to London to track down her estranged father, Mark, and persuade him to come to Holby. Relations between her parents were initially poor - however, in time the pair reconciled, and attempted to rebuild their marriage.
During this period, Owen began dating General Surgical Registrar Diane Lloyd. Chrissie was jealous, especially after they got engaged and enticed Owen to sleep with her the day before the wedding. Disappointed that he had married Diane, Chrissie left things for almost a year between her and Owen. She had a brief affair with Michael Beauchamp - husband of current Clinical Lead Connie Beauchamp, and was instrumental in aiding Connie to bring about his downfall after it was revealed Michael had purposely let VRSA into the hospital, resulting in the death of a young girl. When Owen's marriage to Diane became strained, Chrissie pursued him once more and it seemed that she had won when Owen left Diane for her. However, the death of his ex-wife, Laura, meant that he had to provide a stable home for his daughter, Katie, so Owen resigned from the hospital and told Chrissie that his daughter had to come first. After losing Owen, Chrissie's life was dominated by her parents' relationship and she learned that Mark is not her father, causing another rift with her mother. To this day, Chrissie is unaware that Mark is her half-brother as Tricia was raped by Mark's father, Frank Williams. The pair only began to reconcile when, after her parents' remarriage, Chrissie discovered Tricia's cancer had returned. She was initially angry at being kept in the dark but accepted her mother's decision, following a heart to heart with Diane. Tricia and Mark set off on a second honeymoon, ecstatic that Tricia was in remission again but they were involved in a car crash en route. Chrissie was devastated when later that day, Tricia succumbed to her injuries, and they were asked to switch off her life support. After her mother's death, Chrissie came to increasingly rely on the support and friendship of Cardiothoracic Registrar Sam Strachan. The pair became quite close, however their blossoming relationship was damaged when Sam told her that he was the father of Connie Beauchamp's child and finding fourteen-year-old prostitute Jade McGuire in Sam's bed. Weighed down by events since her mother's death, Chrissie took a leave of absence and returned in episode 'Deep Dark Truthful Mirror', her future at the hospital and her relationship with Sam, remains to be seen.
In December 2007, sexual health nurse Tim attacked three people with a cross bow - shooting Faye, Zoe and Martha Hope. Chrissie was the only member of staff to witness this. Martha and Faye survived the shooting but Zoe didn't make it. Martha and Chrissie found themselves trapped in a lift - the lift was disabled during the aftermath of the shooting. In the lift, Martha had bled and Chrissie promised her that she will do something about her brother James's court sentence, which led Mark to be a witness. Later, Chrissie and the security officer found Tim on the stairs, feeling remorseful. Chrissie took the crossbow from him and he later committed suicide.
On 5 February 2008, Chrissie was taken hostage by her ex-boyfriend, Stuart McElroy, who slashed her face with a scalpel. He gagged her while he stitched her wound. However, Chrissie knocked over a tray, which Connie heard and was rescued by Connie. On 12 February, Chrissie went into hiding and Stuart tried to convince Connie that Chrissie had slashed her face herself. Connie wasn't fooled, however, and persuaded Chrissie to help set him up. Chrissie was sitting in Connie's office when Stuart walked in. Stuart apologised for his actions and confessed, unaware that the conversation was recorded and made a run for it, so Sam and the security guard went after him. After catching him, Sam punched Stuart to the ground and Stuart was arrested. Connie told Chrissie that she will be scarred for life. Chrissie decided to leave Holby, to clear her head after the attack and returned in January 2009. She wasn't pleased to see her father's relationship with Daisha Anderson, questioning the nature of it. After Daisha allowed her sister to take her baby son home to the Philippines, Daisha, thanks to Chrissie, also questioned Mark's feelings for her and moved out.
When junior doctors, Oliver and Penny Valentine, joined the hospital, Oliver makes friends with Daisha and Chrissie. He and Chrissie have a brief relationship which ends by mutual agreement but Chrissie discovers she is pregnant. Unfortunately she miscarries not long afterwards, and is later challenged Mark to find her a man and she will find him a woman. A few months later, Chrissie is pregnant by new doctor Sacha Levy but seems to be embarrassed by him. When she falls ill, Sacha calls Paradis Bloom, a fantastic midwife. As Chrissie's condition deteriorates, her baby boy is born by emergency C-section. Sacha asks Chrissie if she would meet his mother, which she does. She also meets his daughters, Rachel and Beka, but they drive Chrissie up the wall. Chrissie names her son Daniel Levy Williams and says that Sacha can see him whenever he wants and that he is part of their family but she isn't. Chrissie then gets the all clear and went on maternity leave. Chrissie returned in November 2010 and started flirting with Greg Douglas and went on a night out with him whilst Sacha looked after the baby but that soon ended.
A patient called Patrick Wright goes into surgery and nearly dies, due to Jac Naylor's mistake. Jac had an interview that day and was determined to get the job, so she changes his INR result from 4 to 1.4, trying to make Chrissie look incompetent which leads to a complaint being made against her and Chrissie. Chrissie takes it badly and became closer to Sacha. Chrissie is cleared and promoted to Nurse Consultant, with Orthopaedic Consultant Dan Hamilton as her mentor. They begin dating when Dan's rugby friend is admitted with a nasty knee infection, caused by steroid shots administered by Dan. When Chrissie and ward registrar Antoine Malick find out about this, they are both annoyed. When Sean's surgery isn't as straight forward as expected, he is left with a limp. Dan gets frustrated and in the locker room, fights with Malick, but ends up kissing him. He then runs to Chrissie and drags her into the On-Call Room for sex. Dan and Malick continue to argue on the ward and when Dan takes credit for Malick's work, Malick punches Dan leaving him with a cut on his face. Chrissie is determined to find out what happened and when she finds out about the punch, she tells Hanssen. Dan and Malick then have to explain themselves. Dan comes out gay on his and Chrissie's wedding day, humiliating her. However, she soon realises when Sacha tries to cheer her up that she is the man for him, and they start a relationship.
They quickly become engaged, and marry in the following Autumn. However, soon after, Sacha is stabbed and put in a serious condition. Chrissie and Malick manage to save him, and he is soon back to himself. Sacha is devastated to lear that his daughter Rachel has leukemia, and Chrissie struggles to support him. She is unhappy when it is discovered that Daniel is the only bone marrow match for Rachel, and Sacha uses him without Chrissie's knowledge despite the risks involved. After a rocky few weeks, they separate and Chrissie leaves for Australia with Daniel.
She returns a few weeks later without telling Sacha that she is back, and confides in her colleague Michael Spence that she has found a lump in her breast. Further tests reveal that she has breast cancer. Sacha becomes suspicious that Chrissie and Michael are having an affair, but is devastated when he discovers the truth. He later returns home with Chrissie to show Daniel a stable family; however, their separation continues.