The US senate has confirmed school choice activist Betsy DeVos as education secretary, with Vice President Mike Pence breaking a 50-50 tie.
The senate historian said it was the first time a vice president has had to break a tie on a cabinet nomination.
Two Republicans joined Democrats on Tuesday to vote to derail Ms DeVos’s nomination.
Democrats cited her lack of public school experience and financial interests in organisations pushing charter schools.
Ms DeVos has said she would divest herself from those organisations.
Republicans Susan Collins, of Maine, and Lisa Murkowski, of Alaska, fear that Ms DeVos’s focus on charter schools will undermine remote public schools in their states.
Ms DeVos, a wealthy Republican donor and longtime school choice advocate, has emerged as one of Mr Trump’s most controversial cabinet picks.
Labour unions have bitterly contested Ms DeVos’s nomination, fearing that she will undermine public education by promoting charter schools and publicly funded voucher programmes for private schools.
Mr Trump stood behind his nominee, accusing Democrats of fighting progress and change.
"Senate Dems protest to keep the failed status quo," Mr Trump tweeted before the vote.
"Betsy DeVos is a reformer, and she is going to be a great Education Sec. for our kids!"