The actress plans to run in the Democratic Primary against current Governor Andrew Cuomo.
Nixon, who was born in New York, was rumored to run in the gubernatorial race for months. She posted her official announcement to Twitter on Monday, along with an ad and a link to donate to her campaign. Her website had trouble loading, seemingly overwhelmed by traffic.
"New York is my home," she said in the ad, which depicts Nixon in her home with her family, taking her son to school, walking through Manhattan, and riding the subway. "I've never lived anywhere else. When I grew up here, it was just my mom and me in a one-bedroom, fifth-floor walk-up. New York is where I was raised and where I'm raising my kids."
She continued: "I'm a proud public school graduate and a prouder public school parent. I was given chances I just don't see for most of New York's kids today. Our leaders are letting us down. We are now the most unequal state in the entire country, with both incredible wealth and extreme poverty. Half the kids in our upstate cities live below the poverty line. How did we let this happen? I love New York. I've never wanted to live anywhere else, but something has to change. We want our government to work again on health care, ending mass incarceration, fixing our broken subway. We are sick of politicians who care more about headlines and power than they do about us."
The ad also included footage of Nixon giving political speeches at various events including a Human Rights Campaign gala, the People's State of Union event, last year's Stonewall Inn LGBTQ rally, the 2017 Women's March on New York City and the 2009 National Equality March in Washington, D.C.
She told Al Roker, Dylan Dreyer and guest host John Cena on the Today show in August that she had been urged to run.
"I think there are a lot of people who would like me to run for a variety of reasons," she said. "And I think the No. 1 is education."
The mom of 20-year-old Samantha, 14-year-old Charles Ezekiel and 6-year-old Max Ellington has spoken about education and immigration.
"Gov. Cuomo likes to say we spend more per pupil [than] any other state. And that is actually true, but the only reason that is true is that we spend so much in our wealthiest districts. So that evens out," she said on Today. "Between our hundred richest schools and our hundred poorest schools, there's a $10 dollar gap on what we spend per pupil."
Outside New York's Stonewall Inn in February 2017, she denounced President Donald Trump's proposed immigration ban.
"We must fight hard and yell loud for ourselves," Nixon said. "We have come too far to be turned back now, but we must fight just as hard and yell just as loud for Muslims — both those here and those trying to get here."
Having married her wife Christine Marinoni in 2012, Nixon is also an outspoken activist of her fellow LGBTQ citizens.
"We are not rolling back the tarp on the progress that we have made," she wrote in a Variety op-ed in 2015. "To every woman here who won't give up, women make the change."