Mark Behar is a licensed PA (Physicians Assistant). Mark was heavily involved in local gay health & activist politics in the 1970s, 1980s, and 1990s. In the areas of health, Mark was the first director of the GPU VD Clinic, and changed the course of that facility from a testing center to a diagnosis and treatment facility (1977-79). He was a cofounder of a national professional group, the Lesbian, Bisexual, & Gay Physician Assistant Caucus of the American Academy of Physician Assistants (1979). Also in 1979, Mark volunteered at the Chicago Conference on Current Aspects of Sexually Transmitted Diseases Symposium to form the National Coalition of Gay Sexually Transmitted Disease Services (NCGSTDS), and was that group's newsletter editor for the next 10 years. In the early 1980s, Mark was one of the first people in Milwaukee to openly talk about HIV/AIDS to the media (long before the doctors in town chose to do so).

In activist politics, Mark served on Governor Tony Earl's Council on Lesbian & Gay Issues in the mid 1980s, and helped guide the State's response to the HIV/AIDS, and gay & lesbian health issues.

As an offshoot of Mark's involvement in health and activism combined, in the late 1980s-early 1990s Mark was the executive producer of the Milwaukee Gay Lesbian Cable Network, and produced & coproduced over 100 programs for public access TV, including Tri-Cable Tonight. (Mark assisted in ensuring the preservation of most of these programs by helping with the transfer of existing tapes to the UWM Archives in 2003.)

As of 2022, Mark remains active in Milwaukee's GLBT community, and contributes at times to the web site "gayhealth.com". His professional and personal affiliations include the following: