A Massachusetts equality lawyer who fought against the Defence of Marriage Act made history this week, becoming the first out Attorney General in a US state.

Lawyer Maura Healey, who lives with her same-sex partner, was chosen by Massachusetts voters over her rival John Miller last night.

She will now replace incumbent Martha Coakley as Massachusetts’ attorney general.

Following her win, she said: “I’m so proud to be standing here as your next Attorney General. I will give it everything I’ve got every day.”

“As Attorney General I’m going to be your lawyer. I’m going to be your advocate.”

Despite being considered an outsider in the race, the candidate – who was backed by the Gay & Lesbian Victory Fund and the Human Rights Campaign – had trounced former state senator Warren Tolman by 62.4 percent to 37.6 percent in the Democratic Primary.

Human Rights Campaign President Chad Griffin told the Huffington Post: “Maura Healey is one of the staunchest advocates for equality we have in this country, and we join her in celebrating her historic victory tonight.

“As the nation’s first openly gay attorney general, she is an inspirational trailblazer and will fight to guarantee civil rights and legal equality for all people of Massachusetts.”