"Eric brings many years of proven experience and exceptional leadership to this new role," Obama said in a statement. "I am confident he will help lead America's soldiers with distinction."
Advocacy groups said the nomination of an openly gay man to lead a U.S. service branch was a significant sign of progress in protecting the rights of LGBT individuals serving in the world's most powerful military.
The Pentagon updated its equal opportunity policy in June 2015 to bar discrimination on the basis of sexual orientation — a change in policy that Carter announced at a gay and lesbian pride celebration.
That change brought the Pentagon's rules into conformity with the 2011 decision to end the military's "don't ask, don't tell" policy, which allowed gays and lesbians to serve in the military only if they did not openly acknowledge their sexual orientation.
"The Department of Defense has been in a lot of ways a leader in LGBT rights, both in the Obama administration and in government in general," said Matt Thorn, the interim executive director of OutServe-SLDN, an advocacy group for LGBT military personnel.
But LGBT individuals face lingering inequalities in the military, he said. Same-sex spouses may not accompany service members for deployments to many overseas bases, such as those in Gulf countries, he said.
The LGBT community is awaiting the results of a study on the implications of lifting a ban on transgender individuals serving openly in the military, the results of which are expected toward the end of this year, Thorn said.