Mary Elizabeth Taylor, who was unanimously confirmed as assistant secretary of the State Department for legislative affairs in 2018, wrote in her resignation letter on Thursday obtained by the Washington Post that "The President's comments and actions surrounding racial injustice and Black Americans cut sharply against my core values and convictions."
"Moments of upheaval can change you, shift the trajectory of your life, and mold your character," she wrote.
"I must follow the dictates of my conscience and resign as Assistant Secretary of State for Legislative Affairs," she said.
Taylor, 30, before joining the State Department worked for Republican Senate Majority Leader Mitch McConnell and in the White House.
She was the first African American woman and the youngest person ever to serve in the role.
The protests across the US erupted in response to the police killing of George Floyd, who died after a Minneapolis white police officer knelt on his neck for nearly nine minutes on May 25.
Since then, Trump has threatened to deploy troops to crush demonstrators protesting against police brutality and racism in the United States and staged a photo op at a church near the White House after law enforcement fired tear gas and pepper rounds at peaceful protesters from the area.
Taylor earlier this month sent a message to about 60 other State Department employees, expressing solidarity with those who were also in pain over Floyd's death, according to the Post.
"George Floyd's horrific murder and the recent deaths of other Black Americans have shaken our nation at its core. Every time we witness these heinous, murderous events, we are reminded that our country's wounds run deep and remain untreated," her note said.
Critics have described Trump’s response as “woeful” and slammed his attempt at police reform that could not address systemic racism.
In a Rose Garden ceremony on Tuesday, the Republican president signed an executive order on police reform after weeks of protests over the brutal death in custody of an unarmed black man and widespread calls for action against such police behavior.