As deputy national security advisor, 65-year-old Fox News commentator Kathleen Troia "KT" McFarland, will return once again to the executive mansion as number two to former general Mike Flynn.
"She has tremendous experience and innate talent that will complement the fantastic team we are assembling," Trump said, in a statement issued from his luxury Florida golf resort.
White House national security roles do not need to be confirmed by the Senate, so McFarland will take up her duties when President Barack Obama passes Trump the baton on January 20 next year.
She has never herself held elected office, but in 2006 was defeated in a bid to seek the Republican nomination to challenge then New York senator Hillary Clinton's successful re-election bid.
Her most prominent roles before joining Fox News were as deputy assistant secretary of defense for public affairs under president Ronald Reagan and between 1982 and 1985 as defense secretary Caspar Weinberger's speechwriter and spokeswoman.
McFarland's appointment came as Trump was ensconced with senior advisors in his Mar-a-Lago resort drawing up transition plans. A spokesman said no more major decisions are expected before Monday.