Judge Kollar-Kotelly has sided with transgender plaintiffs who claimed the law violated their rights. She ordered the Pentagon to revert to the Obama-era norm that would allow transgender people to serve openly.
A federal court on Monday blocked US President Donald Trump's ban on transgender people in the military, citing the "inherent inequality" in the law.
A moratorium on the Defense Department paying for gender reassignment surgery was upheld.
Former President Barack Obama had taken the historic step of allowing transgender personnel to serve openly in the armed forces. The ruling also barred anyone from being discharged on the basis of gender identity. The decision was originally meant to take effect at the start of 2018, but the Trump administration announced in July that there would be a six-month delay in implementing the rule.
One month later, Trump signed a memorandum reversing Obama's decision, writing on Twitter that transgender individuals could not serve "in any capacity." He then ordered the Pentagon to draft by March 2018 new policy on transgender service members.
Revert to the status quo
US District Judge for the District of Columbia Colleen Kollar-Kotelly has now ordered the US government to "revert to the status quo" that was in effect before the ban after several transgender people serving in the armed forces launched a suit claiming personal injury as a result of the ban.
White House spokeswoman Sarah Sanders told the press that the Department of Justice was reviewing the decision and referred all questions to the officials there.
es/jm (AP, dpa)