Frank was born of Jewish parents. He has been on the left of the Democratic Party, but as a "prudent liberal", who believes in free market. Frank first entered politics while a doctoral student in political science at Harvard University. He worked for Boston mayor Kevin White and taught at the John F. Kennedy School, a public policy institute at Harvard. While serving in the Massachusetts State Legislature for eight years he completed a degree from Harvard Law School and was admitted to the state Bar.

Barney Frank has represented the Fourth Congressional District of Massachusetts since he was elected to the U.S. House of Representatives in 1980. In 1997, Frank became the second representative in the US to come out as gay, the first having been Gerry Studds in 1983.

He secured the establishment of non-discriminatory employment policies in all federal agencies, and he wrote a revision of the McCarran-Walter Act that removed homosexuality as grounds for denying foreigners entry to the United States; Frank was re-elected in 2000.

Frank is a tireless crusader for all issues surrounding the queer community including total support for gay marriage (his was the loudest dissention against the so-called Defense of Marriage Act), military service, anti-discrimination, and hate crimes legislation.

Frank has lent his voice to many other causes over the years, endorsing a compassionate capitalism ("The rising tide may lift all boats," he is fond of pointing out, "but what happens if you can't afford a boat?") and an involved government.

In 1989, a sometimes hustler named Steve Gobie talked publicly of a relationship with Frank, and made claims that seemed to jeopardise the Congressman's career. Frank chose to confront the charges directly and honestly, and survived with a reprimand from the House of Representatives and little damage to his standing at home.

His lover for 11 years was Herbert Moses (from 1987 to 1998). The proud partisan is now living in Washington D.C. and Boston with his partner.