text: Many of them made headlines - from banning all Muslims entering the US, to building a wall along the border with Mexico.
  But as he and his White House team approach the 100-day mark of his presidency, it is clear he has shifted his stance on a number of key issues.
  Before: As a candidate, Mr Trump derided climate change as a hoax concocted by China, and the regulations of Paris as stifling to American growth.
  After: After three months of prevarications behind the closed doors of 1600 Pennsylvania Avenue, the president came down decisively on the side near the exits. Quitting the Paris deal, signed by nearly 200 countries, will take a few years but this is unequivocally a promise kept.
  Before: One of Mr Trump's trademark rally pledges was to repeal and replace Obamacare - his predecessor's attempt to extend healthcare to the estimated 15% of the country who are not covered.
  It is widely hated by Republicans, who say the law imposes too many costs on business, with many describing it as a "job killer" and decrying the reforms - officially the Affordable Care Act - as an unwarranted intrusion into the affairs of private businesses and individuals.
  After: Within two days of his election he softened his approach, saying he wanted to keep the "strongest assets".
  Then the House Republicans put forward a plan, which the president fully backed, but it was mauled by doctors' groups, hospitals and other parts of the medical industry. The government's own budget office said it would strip insurance from millions of Americans, and its approval rating among the public sank. The Democrats opposed it and several wings of the Republican party were uneasy. It was passed by the House of Representatives but the Senate has said it will rewrite the bill from scratch.
  Before: His vow to build a wall along the US-Mexican border was one of the most controversial of Mr Trump's campaign promises.
  Mr Trump also insisted that Mexico would pay for it.
  After: Mexico maintains it will never pay for it, and even the president has conceded that the US will have to pay up front and then seek reimbursement in some way.
  The US Congress is exploring funding options for the wall, but many Republicans will be unhappy about footing a bill which could rise to $21.5bn (Â£17.2bn), according to a Department of Homeland Security internal report.
  That's much higher than Mr Trump's estimated price tag of $12bn (Â£9.6bn).
  There are also landowners who protest against a "government land grab" - and a lawsuit from an environmental group launched in April.
  "We're building the wall," he said in February. "In fact it's going to start very soon."
  Before: Mr Trump called Nafta "a disaster" and warned that the TPP "is going to be worse, so we will stop it."
  After: Mr Trump pledged to withdraw from the Trans Pacific Partnership (TPP). He did in his first few days.
  And he vowed to renegotiate the North American Free Trade Association (Nafta) and, after threatening to pull out, the White House has said that Canada and the US have agreed to talks.
  Before: Mr Trump initially promised to ban all Muslims entering the US - a "total and complete" shutdown should remain until the US authorities "can figure out what's going on".
  But he switched to "extreme vetting" after he became the party's presidential candidate.
  After: As president, he has introduced two travel bans, which have both become ensnarled by legal challenges. The second was a slightly watered-down version of the first, but a judge in Hawaii said barring people from six mainly Muslim countries, even temporarily, violated constitutional protections against religious discrimination. Another judge in Maryland cited Trump campaign statements as evidence.
  President Trump has railed against "judicial overreach" and hinted that he may take the case to the Supreme Court, but has said little on the matter in a round of media interviews this week.
  Five questions on the revised travel ban
  Before: Mr Trump repeatedly told his supporters that every single undocumented immigrant - of which there are 11.3 million - "have to go".
  After: As polling day approached, his stance began to soften slightly, then after the election he scaled it back to some two to three million deportations of people who "are criminal and have criminal records, gang members, drug dealers".
  The Migration Policy Institute, a US-based think tank, has one of the higher figures for illegal immigrants with criminal records, which it puts at 890,000, including people charged with crossing the border illegally.
  The number of removals peaked in 2012 and has been falling since. It is too early to say if there has been an increase since President Trump's inauguration.
  Reality Check: Is deporting of 'bad dudes' at record rate?
  Trump voter's husband faces deportation
  Before: Mr Trump repeatedly questioned the military alliance's purpose, calling it "obsolete". One issue that bugged him was whether members were pulling their weight and "paying their bills". In one New York Times interview in July 2016, he even hinted that the US would not come to the aid of a member invaded by Russia.
  After: But as he hosted Nato Secretary General Jens Stoltenberg at the White House in April, the US president said the threat of terrorism had underlined the alliance's importance. "I said it [Nato] was obsolete," Mr Trump said. "It's no longer obsolete."
  Before: During a speech in Iowa in November 2015, Mr Trump warned that he would, using an expletive, bomb so-called Islamic State into obliteration.
  After: The president dropped the biggest non-nuclear bomb in the US arsenal on an IS-stronghold in Afghanistan.
  At the site of the Mother of All Bombs
  Before: Mr Trump repeatedly pledged to label Beijing a "currency manipulator" on his first day in office, during an election campaign when he also accused the Asian powerhouse of "raping" the US. China has been accused of suppressing the yuan to make its exports more competitive with US goods.
  After: He told the Wall Street Journal in April that China had not been "currency manipulators" for some time and had actually been trying to prevent the yuan from further weakening.
  Before: "I am looking for judges and have actually picked 20 of them. They'll respect the Second Amendment and what it stands for and what it represents."
  After: He vowed to appoint a conservative justice and he has - Neil Gorsuch. It took a procedural change to Senate rules, but it's a victory nonetheless.
  Before: Mr Trump said he would approve waterboarding "immediately" and "make it also much worse", adding "torture works".
  After: But after his inauguration, the president said he would defer to the opposing belief, espoused by Defence Secretary James Mattis and CIA director Mike Pompeo.
  Mr Pompeo said during his confirmation hearing said he would "absolutely not" reinstate such methods.
  Before: "Lock her up" was one of the main rallying cries of Mr Trump's supporters.
  They wanted to see Democratic rival Hillary Clinton in prison over the use of her private email server while secretary of state.
  And Mr Trump was more than willing to back their calls for, at the very least, a fresh investigation. During the debates, he told Mrs Clinton: "If I win, I am going to instruct my attorney general to get a special prosecutor to look into your situation."
  After: The president-elect's tone changed almost as soon as he had won, describing the woman he had said was "such a nasty woman" as someone the country owed "a debt of gratitude". Later, he said he "hadn't given [the prosecution] a lot of thought" and had other priorities.
  On 22 November, Mr Trump's spokeswoman said he would not pursue a further investigation - to help Mrs Clinton "heal".
  Before: The country's infrastructure "will become, by the way, second to none, and we will put millions of our people back to work as we rebuild it", he said in his victory speech in November.
  After: Has repeated his vow to spend big on the country's roads, rail and airports, but no sign yet of action.
  Before: Mr Trump pledged during his campaign to move the embassy from Tel Aviv to Jerusalem, a divided city which both Israelis and Palestinians claim.
  After: He approved a waiver to keep the embassy in place, but suggested in a statement that it would be eventually relocated. "The question is not if that move happens, but only when," the White House said, adding the decision was taken in order to "maximize the chances of successfully negotiating a deal between Israel and the Palestinians".
target: Donald Trump made a string of promises during his long campaign to be the 45th president of the United States.