Dr. Rachel Levine, the nation’s most senior transgender official, made history again Tuesday by becoming the first openly transgender four-star officer across any of the country’s eight uniformed services.

Levine, the assistant secretary of health, was sworn in Tuesday as an admiral, the highest-ranking official of the U.S. Public Health Service Commissioned Corps, whose 6,000 uniformed officers are entrusted with protecting the nation’s public health. Levine’s appointment also made her the organization’s first female four-star officer. 

“This is a momentous occasion, and I am honored to take this role for the impact I can make and for the historic nature of what it symbolizes,” Levine said in a speech at her swearing-in ceremony. “I stand on the shoulders of those LGBTQ+ individuals who came before me, both those known and unknown. May this appointment today be the first of many more to come, as we create a diverse and more inclusive future.”

Levine, a pediatrician who previously served as Pennsylvania’s health secretary, has spearheaded numerous efforts to combat public health issues, including the opioid epidemic, maternal mortality and childhood immunization. A graduate of Harvard College and Tulane Medical School, she has also written on medical marijuana and pediatric medicine. https://iframe.nbcnews.com/Hnx98sa?app=1

In heading the health corps, Levine will be in charge of deploying the country’s public health workers to respond to crises ranging from the coronavirus pandemic, which has killed more than 725,000 Americans, to natural disasters such as flooding.

Levine said she was proud to follow in the footsteps of her father, who served in the Air Force during World War II, and other members of her family who are veterans.

“Just as they stepped up to defend our rights to freedom and liberty, I now follow in their storied tradition of service as I step up to defend the health of our nation,” she said. 

Out of the eight uniformed services in the United States, including the Army, Navy and Air Force, the Public Health Service Commissioned Corps distinctly focuses on medical issues. 

Levine made history in March when she became the first openly transgender federal official to be confirmed by the Senate. She was narrowly confirmed by a vote of 52-48, primarily along party lines. 

Senior health officials lauded the historic nature of Levine’s appointment to the public health corps for the LGBTQ community, noting its particular significance during LGBTQ History Month, which is celebrated in October. 

“Admiral Levine’s historic appointment as the first openly transgender four-star officer is a giant step forward towards equality as a nation,” Health and Human Services Secretary Xavier Becerra said in a statement.

As the nation’s top transgender official, Levine has previously told NBC News that she will work to support the LGBTQ community, particularly transgender youth, saying “we have to protect those most vulnerable in our community.”

“The time is now for our country to continue to move the bar forward for diversity,” Levine said Tuesday. “And I am proud to wear this uniform and answer that call.”