Rachel Levine (left) became the nation's first transgender four-star admiral on Tuesday when she was sworn in by Vice Admiral Vivek Murthy of the U.S. Surgeon General's office (right)

A President Joe Biden appointee became the nation’s first transgender four-star admiral when she was sworn in to lead the U.S. Public Health Service Commissioned Corps on Tuesday.

Admiral Rachel Levine will serve as head of the USPHS along while maintaining her position as Assistant Secretary for Health for the U.S. Department of Health and Human Services, which made her the nation’s highest-ranking transgender official.

Levine, 63, will lead the nearly 6,000-person force of public health professionals who respond to public health crises, including administering COVID vaccines, and national emergencies on behalf of the federal government.

‘I am deeply honored & grateful to join the ranks of men & women across this great nation who have committed to defend the United States against small & large threats, known and unknown,’ Levine tweeted with a broadcast of her swearing in.

‘I promise to uphold that trust to the fullest extent of my abilities.’