Person Type: Status Unknown
Name: William Mulder
Eye Color: Hazel
Hair Color: Brown
Sex: Male
William Mulder
History: William Mulder, now deceased, was the father of Agt. Mulder. The elder Mulder was a mid-level employee of the State Department engaged in clandestine activities. His association with the Cigarette-Smoking Man dates to their earliest years in the military. Mulder was later involved, to an unknown degree, in a top-secret, covert operation under which former Axis scientists were admitted to the United States to utilize their expertise in medical experimentation, including genetics, immunology, and bio-chemical research. As part of this operation, an attempt was allegedly made to create "hybrid" beings by combining human and alien DNA.

Following a warning by the Cigarette-Smoking Man that Agt. Mulder was near to uncovering the past work of the elder Mulder and his colleagues, William Mulder summoned Agt. Mulder to his home at Martha’s Vineyard. The elder Mulder then attempted to reveal his earlier government work to Agt. Mulder, but had not yet done so when he was shot and killed, allegedly by Alex Krycek.

The apparent abduction of Mulder's daughter Samantha, under circumstances unknown but thought to be related to Mulder's involvement in covert operations, led to the break up of his marriage and a lifelong estrangement from his son, Agt. Mulder. No other details of the elder Mulder's personal history are known.