His statement identifying as trans won swift praise across Hollywood and beyond, with LGBTQ charity GLAAD calling Page "remarkable" and "an outspoken advocate for all LGBTQ people."
"He will now be an inspiration to countless trans and non-binary people," said the group's director of transgender media Nick Adams. "All transgender people deserve the chance to be ourselves and to be accepted for who we are."
Netflix tweeted: "So proud of our superhero! We love you Elliot!"
Page, 33, burst onto the Hollywood scene with an Oscar-nominated role as a pregnant teenager in 2007 sleeper hit "Juno."
The actor also appeared in the 2010 science fiction hit "Inception" opposite Leonardo DiCaprio, and the 2012 Woody Allen comedy "To Rome with Love."
Page came out as gay in 2014, quickly become a flagbearer for Hollywood's LGBTQ community, and married dancer Emma Portner in 2018.
While largely absent from big-budget Hollywood blockbusters since 2014's "X-Men: Days of Future Past," Page has repeatedly shrugged off suggestions of being typecast or shunned by Tinseltown.
Page joins a small group of prominent Hollywood transgender figures, alongside "The Matrix" series writer-directors Lana and Lilly Wachowski, "Transparent" creator Joey Soloway and actor Laverne Cox.
On Monday, Cox described being the victim of a recent transphobic attack in Los Angeles, underlining the hostility facing many transgender individuals in the entertainment industry and beyond.
"The truth is, despite feeling profoundly happy right now... I'm scared of the invasiveness, the hate, the 'jokes' and of violence," wrote Page.
Page also railed against politicians who "criminalise trans health care and deny our right to exist," as well as influential public figures who use "a massive platform who continue to spew hostility towards the trans community."
"You have blood on your hands. You unleash a fury of vile and demeaning rage that lands on the shoulders of the trans community," added Page, noting high rates of attempted suicide among the community.
Alphonso David, president of LGBTQ advocacy group Human Rights Campaign, thanked Page for "sharing your truth with us, and for shining a bright light on the challenges too many in our community face."
Although Page did not name any specific individuals, President Donald Trump's administration has attempted to roll back Obama-era anti-discrimination protections for transgender people in the health care system, and also banned transgender Americans from serving in the military.
Harry Potter author JK Rowling has been at the center of a firestorm in recent years over comments deemed insulting to transgender people.
Rowling sparked controversy in June for tweeting about the use of the phrase "people who menstruate" instead of women - prompting some former fans and activists to call for a boycott of her works.
"You aren't being 'cancelled,' you are hurting people. I am one of those people and we won't be silent in the face of your attacks," wrote Page, addressing transphobia in general.
GLAAD provided a "tip sheet" for journalists covering Page's statement, advising reporters to "use he/they pronouns when referring to Elliot Page."