Dan Siminoski was born in Los Angeles on January 1, 1947, to a progressive family. He displayed his commitment to human rights at an early age, when he co-chaired Mid-City Youth Against Proposition 14, a state-wide initiative to invalidate the California Fair Housing Law. He studied at the University of California at Berkeley, where he was involved in the Free Speech and anti-war movements and became the Berkeley co-chairman of Senator Eugene McCarthy's presidential campaign; he received a BA in Political Science and was elected to Phi Beta Kappa in 1968. Before entering graduate school, Siminoski served as a staff investigator for the Fair Campaign Practices Committee in Washington, DC, and then as legislative aid to Senator Wayne Morse. He earned his MA with honors in Political Science from the University of Wisconsin in 1970, when he was also awarded a Ford Fellowship. His doctoral research brought Siminoski back to Los Angeles where he came out in 1973 and became active in gay rights causes. In 1976-1977, he was an Instructor in the Social Sciences Department at Long Beach City College. He received his PhD in Political Science from the University of Wisconsin in 1978. In 1979-1980, he was Visiting Assistant Professor in the Department of Political Science at Arizona State University, and in 1980-1981, he held the same position at the University of Missouri St. Louis. He was appointed Visiting Lecturer in Political Science at Texas Tech University in 1981.

His long-held interest in gay and lesbian civil rights led Siminoski to file a request with the Federal Bureau of Investigation under the Freedom of Information Act (FOIA) on October 22, 1982, for copies of all FBI Headquarters and field office records relating to the surveillance of gays and lesbians from 1950 to 1982. When the FBI failed to comply with the request fully and in a timely manner, Siminoski, represented by the ACLU Foundation of Southern California, filed suit against the Bureau in Federal District Court in Los Angeles, on October 11, 1983. Simultaneously, Siminoski, who had left teaching and moved to Los Angeles in the late summer of 1983 to devote himself full-time to the impending lawsuit, launched Siminoski vs. FBI 1984 , a speaking tour and media campaign to publicize his case. Although the FBI began releasing documents in quantity to him by the end of the first quarter of 1984, Siminoski continued his case on the grounds that the documents were unnecessarily redacted. In late 1984, Siminoski, whose project had found a home at Jim Kepner s International Gay and Lesbian Archives (formerly Western Gay Archives) at 1654 North Hudson St., initiated the Freedom of Information Project. The purpose of this project was to analyze the documents released by the FBI and to gather signed and notarized Privacy Act Waiver Forms from leading gay activists, with the intention of turning his legal action into a class action lawsuit and expanding the scope of the FBI records sought. Although Siminoski collected properly executed Privacy Act Waiver Forms from a number of prominent gay activists, this latter purpose was not realized.

In 1986, Siminoski, who had supported himself since leaving teaching as a free-lance political consultant and syndicated columnist, withdrew for health reasons from active participation in the lawsuit. In 1988, he earned a master's degree in Social Work from California State University Long Beach. He now lives in San Diego. In November 1988, Ralph J. Geffen, acting as Special Master, reported favorably on most of Siminoski's legal claims; however, many of his recommendations were overruled by Judge William D. Keller in his decision of January 1990, which was not appealed.