For slightly longer than a year, Dr. Glass oversaw Ray Soames' treatment for clinical schizophrenia; according to the doctor, Soames had an inability to grasp reality and seemed to suffer from some kind of post-traumatic stress. By 1992, Dr. Glass had treated similar cases to Soames, some or all of whom had been Soames' classmates. The doctor began treating Billy Miles and Peggy O'Dell – who had been in the class of '89 with Soames – in or prior to March 1988 and the two became longterm live-in patients at the psychiatric hospital at around that month.
Dr. Glass was visited at the hospital by FBI Special Agents Fox Mulder and Dana Scully in March 1992. As the three individuals walked outside the building, the doctor was questioned by Agent Mulder. Dr. Glass confirmed for the agents that Ray Soames had indeed been a patient of his and continued to reveal his own history of not only having treated Soames, but also supervising the treatment of some of Ray Soames' former classmates. When Mulder asked the doctor if he had treated any of Soames' classmates with hypnosis, Dr. Glass slightly laughed and denied that he had. Dr. Glass then revealed to the agents that Billy Miles and Peggy O'Dell were currently undergoing treatment at the hospital and had been patients there for almost four years. Even though Mulder was eager to talk to the two patients, the doctor replied that accomplishing that task might prove difficult and would certainly be so in Billy Miles' case.
In the hospital ward that included Peggy O'Dell and Billy Miles, Dr. Glass explained to Mulder and Scully that Billy Miles was experiencing a condition known as a "waking coma" – meaning that, functionally, his brainwaves were flat and he was persistent vegetative. The doctor also recalled that the condition was the result of an automobile accident on State Road, in which both patients had been involved in. Interrupting Peggy O'Dell as she read a book while sitting in a wheelchair beside Billy Miles, Dr. Glass told Peggy that they had some visitors and asked if she would like to talk with them for a moment, but she insisted that Billy wanted her to read to him at that time. After Mulder approached Peggy O'Dell with a single question, Dr. Glass was taken aside by Mulder and listened as the FBI agent recommended that they do a cursory medical exam on Peggy O'Dell. When she suddenly then started to cause a disturbance and her nose began to bleed, Dr. Glass tried to calm her and contain the situation, aided by Mulder and an orderly, but the agents soon left the hospital. (TXF: "Pilot")
- Dr. Glass was played by Malcolm Stewart. The character's name is never established in the fictional events of the pilot episode, but the character is referred to as "Dr. Glass" in the episode's closing credits and script sources establish his first name as "William". The episode's script also describes the character as "abstruse".