The decision clears the way for official changes to Manning's military records, but does not compel the military to treat the soldier previously known as Bradley Edward Manning as a woman.
That includes not being moved from the U.S. Disciplinary Barracks at Fort Leavenworth, where Manning is serving a 35-year prison sentence, to a prison with a woman's unit, or receiving the counseling and hormone treatment she seeks.
Manning wasn't present at the hearing before Leavenworth County District Judge David King, which lasted just about a minute, but issued a statement after the ruling calling it "an exciting day."
"Hopefully today's name change, while so meaningful to me personally, can also raise awareness of the fact that we (transgender) people exist everywhere in America today, and that we must jump through hurdles every day just for being who we are," Manning said.
Army spokesman George Wright said the only impact of the district court ruling was changing Manning's name on military records, but not the soldier's confinement status.
"Likewise, the U.S. Disciplinary Barracks is a male-only facility and prisoners there are referred to by the title 'inmate'," Wright said in a statement to The Associated Press.
Manning, who grew up in Oklahoma, has been diagnosed by at least two Army behavioral health specialists with gender dysphoria, or gender identity disorder. She filed the court petition as the first step toward getting her Army records changed.
The former intelligence analyst was sentenced in August for six Espionage Act violations and 14 other offenses for giving the anti-secrecy website more than 700,000 secret military and U.S. State Department documents, along with battlefield video, while working in Iraq in 2009 and 2010. An Army general upheld the convictions last week, clearing the way for appeals with the Army Court of Criminal Appeals.
There was no Army opposition filed to the name-change petition, with which Manning included several newspaper reports indicating the desire to live publicly as a woman last August, as well as copy of an Oklahoma birth certificate.
Manning has filed a grievance with the U.S. Disciplinary Barracks commander at Fort Leavenworth over the lack of a response to her request for comprehensive treatment for her gender identity disorder, including specialized gender counseling and hormone replacement therapy.
Emma Cape, a member of the Chelsea Manning Support Network, said in an email to The Associated Press that Manning was told several months ago that a medical plan of treatment had been developed, but it had yet to be implemented or discussed with Manning.
Cape said an attorney for Manning would be working on further legal action following completion of the name change.
"Access to a counselor specialized in gender issues and hormone therapy would be some of the initial steps typically taken when an individual first starts pursuing treatment for gender dysphoria," Cape said. "Chelsea wishes to have access to a counselor who can guide her in this process, and help her decide what additional treatments she may or may not want to pursue."
The military has said it doesn't provide hormone replacement therapy. Gender dysphoria generally disqualifies one for military service, but Manning can't be discharged while serving the prison sentence.