"The act does not require that people who, having undergone a sex affirmation procedure ... must be registered, inaccurately, as one or the other," the court found.
Despite its ruling, the court repeatedly refers to Norrie as "she" and "her" in its judgment, citing that Norrie's legal representatives used the terms in submissions.
Norrie's lawyer, Scott McDonald, described the case outcome as a "persuasive authority" for other jurisdictions.
"It'll be binding on the states that have identical or similar legislation," he told reporters.
And for states such as Western Australia, with very different legislation, the judgment has sent a message the High Court doesn't think gender is limited to male and female.
The court was asked to consider whether "non-specific" can be included as a third gender category under the Registry's Act.
Lawyers for the Registry argued unacceptable confusion would flow from the acceptance of more than two gender categories, and that the purpose of a reassignment procedure is to assist a person to be considered a member of the opposite sex.
But counsel for Norrie said it is the register's purpose to record the truth.
"Norrie's sex remained ambiguous so that it would be to record misinformation in the register to classify her as male or female," a judgment summary reads.
For Norrie, Wednesday's ruling was "very exciting".
"Many other people let me know they wanted (to identify as non-specific) in Australia and indeed around the world," Norrie told reporters in Sydney.
The Human Rights Law Centre said it was important that identity documents such as birth certificates give equal recognition to gender diverse people.
"It's essential that our legal systems accurately reflect and accommodate the reality of sex and gender diversity that exists in our society," spokeswoman Anna Brown said.
Community support group A Gender Agenda spokesman Sam Rutherford said all states and territories would have to pay attention to the judgment.
Norrie's application for non-specific status should now be reconsidered by the Registry in accordance with the court's finding, the judgment said.
The Registry must pay Norrie's costs of the High Court appeal.
- AAP
