Born in raised in San Francisco, CA, where he graduated from Lowell High School in 1977, Mark Harrington joined the seminal AIDS activist group, ACT UP (the AIDS Coalition to Unleash Power)/New York in 1988, five years after receiving his bachelor’s degree in history and photography from Harvard University. As a member of ACT UP’s Treatment and Data (T+D) Committee, Mark helped plan and execute ACT UP’s “Seize Control of the FDA” demonstration in 1988 and its “Storm the NIH” demonstration in 1990. The events helped initiate a fundamental shift with how the U.S. Food and Drug Administration (FDA), the U.S. National Institutes of Health (NIH), and other government agencies addressed the emergency posed by the HIV pandemic in the United States. In 1992 Mark co-founded the Treatment Action Group (TAG) with a group of T+D members to form a long-term non-profit non-governmental organization dedicated to advocating for research, treatment, prevention, and cure of HIV/AIDS. Mark wrote and edited many reports for ACT UP and TAG, including three editions of the National AIDS Treatment Research Agenda (1989–91). At the Eighth International AIDS Conference in Amsterdam in July 1992, Mark delivered a plenary address entitled “Pathogenesis and Activism,” using slides of his own HIV-infected lymph nodes to illustrate critically important unanswered questions about the basic science of HIV infection. In 2000, TAG expanded its work to focus on the leading coinfections killing people with HIV around the world, tuberculosis (TB) and hepatitis C virus (HCV). Mark served on the U.S. Department of Health and Human Services (DHHS) Panel on Antiretroviral Guidelines for Adults and Adolescents from 1996 to 2008. He was a member of the writing group that produces and updated the World Health Organization (WHO) Guidelines for Antiretroviral Therapy for HIV Infection in Resource-Limited Settings, 2002—2010, and a member of the WHO advisory groups for tuberculosis (TB) and for HIV and of the Stop TB Partnership’s Global TB/HIV Working Group and its Multidrug Resistant (MDR)-TB Working Group. Since 2002 Mark has been executive director at Treatment Action Group. Mark has coauthored papers published in The Lancet, PLoS Medicine, Science. Currently Mark is a member of New York State’s AIDS Advisory Council’s Ending the Epidemic (EtE) Subcommittee, the AIDS Clinical Trials Group (ACTG) Tuberculosis Transformational Science Group (TB TSG) and the ACTG/IMPAACT networks’ joint A5300B/IMPAACT 2003B/PHOENIx “Protecting Households On Exposure to Newly Diagnosed Index Multidrug-Resistant Tuberculosis Patients (PHOENIx MDR TB)” protocol team. He lives and works in New York City.