President-elect Donald Trump has chosen Don McGahn, a well-known campaign finance lawyer, as his White House counsel, and K.T. McFarland, a national security analyst, to be his deputy national security adviser, a transition official said on Friday.

"Don has a brilliant legal mind, excellent character and a deep understanding of constitutional law," Trump said in a statement on Friday. "He will play a critical role in our administration, and I am grateful that he is willing to serve our country at such a high-level capacity."

McGahn, Politico reported, has a familial ties with the president-elect. His uncle was a longtime lawyer for Atlantic City casinos; Trump was among his clients until firing him in the early 1990s, then sued him for overbilling legal fees.

The D.C. insider is former chairman of the FEC and apparently highly regarded among Washington Republicans – as The Hill reported, his appointment is an indication of Chief of Staff Reince Priebus' influence on Trump.

Meanwhile, McFarland is the third female appointed to Trump's cabinet, after South Carolina Gov. Nikki Haley as U.N. ambassador and businesswoman Betsy DeVos as education secretary earlier this week. 

McFarland gained experience in national security and defense positions in the Ford and Reagan administrations, and – ironically – ran against Trump's Democratic challengeer Hillary Clinton in New York's Senate race in 2006, though she lost to Clinton's reelection. 

"I am proud that KT has once again decided to serve our country and join my national security team," Trump said in an official statement. "She has tremendous experience and innate talent that will complement the fantastic team we are assembling, which is crucial because nothing is more important than keeping our people safe."

In her own statement released by Trump's team, McFarland praised the president-elect: "The American people chose Donald J. Trump to lead them for a reason. He has the courage, brilliance and energy to Make America Great Again, and nobody has called foreign policy right more than President-elect Trump, and he gets no credit for it. I'm honored and humbled that he has asked me to be part of his team."

Reuters contributed to this report.