Keith Dennison was the father of Tricia McNeil and Megan Dennison Viscardi. Keith took care of his daughters alone and was overprotective of them, especially of Tricia during her relationship with Ryan McNeil.
In 1996, Jill Abbott became involved with Keith. Keith proposed to Jill, but she turned him down.
In 1997, behind Victor Newman's back, Jill and Jack closed a business deal with businessman Keith.
Keith was against Tricia and Ryan's marriage and was worried that his daughter might end up hurt. After Tricia miscarried, she began acting strangely and committed a number of crimes before leaving town with Keith.
In 1999, Keith returned to Genoa City, once again to take care of Tricia, whose mental health was worsening. Keith decided to institutionalize his daughter, but she recovered, even though Keith did not believe her. Tricia tried to kill her father one day, but he suffered a stroke and ended up in the hospital and became comatose. Tricia reacted quickly. Knowing that the Newmans would want her back in the mental hospital now that Keith was incapacitated and couldn't watch over her (Tricia's sister, Megan, was also unavailable), Tricia gave Victor an unusual proposition: She would move into the penthouse with him, where he could keep an eye on her himself.
In 2001, Victoria Newman sat at her desk and placed a call to Keith. Victoria told Keith's secretary that it was urgent she speak with him. Believing that Neil Winters told Ryan of her intentions, Victoria spilled the beans to an unsuspecting Ryan. Victoria hadn't done anything yet but thought it would be good for Tricia to go to London. No one answered, so she left a message. Victoria tried to call Keith once more with no success. Ryan came in and they immediately began arguing about her provoking Tricia in some way and the fact that she should stay out of the situation. They went back and forth to no avail, then the secretary announced a telephone call for Victoria -- it was Keith. Ryan couldn't believe Victoria was trying to bring Keith into her plot against Tricia. He begged her to keep Tricia's father out of it. When speaking to Keith she covered by asking him about networking solutions for Brash & Sassy. Before hanging up, he asked her about Tricia and Ryan. She claimed that she hadn't seen much of them. After the call, Ryan blasted her for calling Keith. She claims she called him to help Tricia. Ryan thought she was full of it and was thinking only of herself. She didn't believe she did anything wrong. She was only looking out for Ryan, she swore. He told her to back off and if she didn't he would never have anything to do with her again.