Prior to that, she served as a press aide for Donald Trump's first presidential campaign and on his transition team, worked on Republican Mitt Romney's 2012 presidential campaign and ran her own small public relations firm.
Grisham has been a valued lieutenant to the first lady, though that has not made her immune from the everyday scandals and controversies of the Trump White House. She had led the First Lady's Be Best campaign and organized her first major solo trip overseas previous year.
Sanders announced her plans to step down as White House press secretary earlier this month.
Other potential candidates thought to be under consideration were Deputy Press Secretary Hogan Gidley, former State Department spokesman Heather Nauert and Tony Sayegh, who recently left his job as Treasury Department spokesman. Those events have become increasingly rare under Sanders; there hasn't been a formal daily press briefing in more than three months, with President Trump mostly addressing press questions in quick-hit moments before boarding Marine One on the White House lawn.
Mexico sends almost 15,000 troops to the USA border
He said another 2,000 National Guard troops had already been deployed to the country's southern border with Belize and Guatemala. The decision to deploy troops to Mexico's northern border is a different approach than the country has normally taken.
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U.S. sanctions Iran supreme leader; plans to designate foreign minister
Mr Trump said the additional sanctions were in response to the shooting down of a USA drone and "many other things". Iran has responded to the economic pressure by saying it planned to violate some of the nuclear deal's commitments.
In an unusual move, after then-deputy national security adviser Mira Ricardel tangled with the East Wing ahead of the first lady's solo trip to Africa, Grisham issued a statement calling for her to be removed from her role. "I will miss her honest love of country & great sense of humor at the @WhiteHouse - no matter what the future holds, I wish her (and her attractive family) the very best!" She's tough and she's good, ' Trump gushed in remarks before she took the podium to speak, adding that she is a 'warrior'.
Trump has appointed Grisham both White House director of communications as well as press secretary, a senior White House official tells CNN.
'I've learned a long time ago never to rule anything out, ' she said during a talk with reporters in her office in the West Wing. She won't talk to us anymore, ' he quipped, praising his exiting press secretary.
'Sarah has done a fantastic job, she'll be governor.