President Obama has nominated to the position of US army secretary Eric K Fanning, who if confirmed will become the first openly gay civilian to lead a branch of the US military.

Fanning, an adviser to defense secretary Ash Carter, has been acting undersecretary of the army since June and has also held leadership roles in the navy and the air force. He began working at the Pentagon when the US military still prohibited openly gay service members to remain in uniform.

Together, Fanning and his planned successor as undersecretary, Patrick J Murphy, were crucial to the repeal of the “don’t ask, don’t tell” policy in 2010. Murphy, a former congressman who was nominated last month to the position, introduced the bill to repeal “don’t ask, don’t tell”. The two jobs are the top civilian positions in the US army and together share leadership of the service with general Mark Milley, who began his post in August.

“Eric brings many years of proven experience and exceptional leadership to this new role,” Obama said. “I am grateful for his commitment to our men and women in uniform, and I am confident he will help lead America’s soldiers with distinction. I look forward to working with Eric to keep our army the very best in the world.”

In a 2013 interview with the Washington Blade, Fanning described working at the Pentagon while “don’t ask, don’t tell” was still in effect. “That wasn’t a particularly fun experience listening to the senior generals and admirals talk about those issues – now it was 20-plus years ago,” he said. “It made this last round more rewarding just to see the change in the attitudes in the senior uniform leadership.”