Her husband, an attorney who renounced Trump after the 2016 campaign, had become a member of the Lincoln Project, an outside group of Republicans devoted to defeating Trump.
The politically adversarial marriage generated much speculation in the Beltway and online.
George Conway also announced Sunday that he was taking a leave of absence from both Twitter and the Lincoln Project.
Kellyanne Conway worked for years as a Republican pollster and operative and originally supported Sen. Ted Cruz in the 2016 Republican primary.
She moved over to the Trump campaign and that August became Campaign Manager as Stephen Bannon became campaign chairman; Bannon was indicted two days ago for fraud.
Conway cited a need to help her children's remote learning during the coronavirus pandemic as a need to step away from her position.
She had remained a trusted voice within the West Wing and spearheaded several initiatives, including on combating opioid abuse.
She was also known for her robust defense of the president in media appearances, at times delivering dizzying rebuttals while once extolling the virtues of “alternative facts" to support her case.