Willow is a former member of "Dawn of Day" and has a past with Hank Archer, who is revealed to be the father of her child.
It’s also later revealed that Willow's birth name is Kali Miller. Willow and "Dawn of Day" member Harmony Miller share the same last name and it's later revealed that Harmony is actually Willow's mother.
On April 23, 2019, Willow admits that Harmony is her mother while in a conversation with her. The conversation also leads to Willow breaking down because Harmony forced her own daughter to be a part of the trust and have sex with Shiloh. Harmony also knew about Willow's pregnancy because she found the pregnancy test.
Willow was first mentioned in a letter sent home from school with Aiden on October 12, 2018. Franco and Elizabeth meets with her when he starts acting distant at school since his friend Josh left. She's next seen illegally parked at General Hospital. Det. Chase thought she was drunk but she said she was just tired. Her car breaks down, and Lulu helps her fix it and mentions to Chase that she was single. Chase sees a brochure for grief counseling, he tells her there's nothing wrong with dealing with grief. Later she's seen attending the meeting at GH, Michael ends up at the same meeting.
In November, she noticed on how Charlotte is bullying her cousin Aiden in class and becoming disrespectful to anyone she doesn't like. She soon relays this to her parents as they need to talk to their daughter and make it clear that this isn't acceptable.
On December 21st, it was revealed that Willow Tait is the biological mother of the deceased child Brad and Lucas adopted. It was also revealed that Julian convinced her to give up her son to Brad and Lucas. Willow has no idea that her son died.
In 2019 Willow started dating Port Charles police detective Chase and she also becomes friends with Michael Corinthos because they were in the same grieving parents' group.
In March 2019, it revealed Willow was part of "Dawn of Day," where she met Hank under the name Shiloh. When Shiloh discovered Willow was up to no good he kicked her out of the "Dawn of Day" house, as Shiloh described it, but we've come to know that's not the full story.
On March 25, it's revealed that Shiloh is the father of her son.
On April 23, 2019, Harmony finds Willow. She tells her that she will never get used to her new name and that she misses her. She also tells her that she is welcome to come back to the DOD house, despite the scene she caused when she left the first time. Willow tells her that she likes her new life and the job that she has, and she also tells her that she will never come back because of the things that were done to her and the things that she, her mother, let Shiloh do to her. Harmony also knows about her baby. When Harmony asks about the baby, she lies to her and tells her that she had a miscarriage. Willow leaves after Harmony breaks her down.
On May 21, 2019 at the Nurse's Ball Willow was talking on the phone to Diane Miller about her "son" "Wiley" and Nina overheard her. She asked about her child and Willow got into an argument with her and Shiloh overheard. He then confronted Willow about their child together and Willow tried to dodge him by saying she lost the baby but he didn't believe her. As Shiloh assaulted her and was threatening her Michael grabbed him and threw him on the ground in her defense. After Willow calmed down with Michael's help she told him that Shiloh knows about the baby she gave up and eventually Lucas confronted her about hiding "Wiley" from Shiloh. She then explained why she did what she did and Michael pointed out that they all have to work together to protect "Wiley" from Shiloh.
In June 2019, Willow was summoned to court in a custody battle and Diane advised her to show up on time. Willow was trying to leave the school to get to court but she kept getting stopped because the principal reinstated her as a teacher at PC elementary school. Chase came and she left with him. When they finally got to court Diane said that they're on recess and that Judge David Walters would be ready to rule when the court reconvenes. Judge Walters came out and ruled in favor of Shiloh and ordered Willow to turn over any documents on her "son's" whereabouts. Diane tried to get the case thrown out but Willow finally snapped and admitted that she had his child and that he would never find him. That reinforced Judge Walters' decision to have Willow turn over documents on her "son's" whereabouts and she refused so he ordered the bailiff to take her into custody for contempt of court, but Chase said he would handle it. Judge Walters allowed him to and a heartbroken Chase had no choice but to arrest Willow.
Later on, Chase brought Willow into the interrogation room and gave her a cup of chamomile tea and they discussed their next move. Chase initally wanted Willow to cooperate with the judge but after learning from Michael that Shiloh murdered her dad, Douglas Miller, he changed his mind and told Willow not to cooperate.