-Gorsuch joins the ranks of justices who are millionaires. "He was beloved by many, very many, who are here today, and he is deeply missed by all of us".
He showcased a rare domestic victory after a chaotic first few months in office marred by legal troubles over his travel ban, the failure of his effort to repeal the health care law, and intense feuding inside his senior team.
Gorsuch's confirmation process, too, was marred by an extraordinary degree of partisanship.
"He will decide cases not based on his personal preferences but based on a fair and objective reading of the law", Trump said of Gorsuch.
"We will ensure that for the Supreme Court, there is that special margin that any candidate has to reach because that is essential to ensuring that our country has a confidence in those people who are nominated", Markey added.
Those attending included liberal Justice Ruth Bader Ginsburg, who called Trump "a faker" during the presidential campaign but later said she regretted the remark.
Gorsuch took the oath of office-taken by public servants in all USA government branches-at the private ceremony scheduled for 9 a.m.at the Supreme Court. Gorsuch, only 45 years old, is expected to serve for many years.
Gorsuch will replace the late conservative Justice Antonin Scalia, who passed away in February of 2016. He then went to the White House to take a second "judicial oath" in a public ceremony. The first was administered earlier that morning by Chief Justice John Roberts with Scalia's widow and one of his sons in attendance, as well as the other eight Supreme Court justices.
Gorsuch's confirmation comes at the end of a long, unseemly, petulant, politically and civically corrosive sequence of events that has gone on now for more than a year, and from which nearly no one involved has emerged unsullied.
Gorsuch's confirmation process was a bitter battle in the Senate, as the opposition Democrats blamed the Republican majority for refusing to consider President Barack Obama's nomination to the court, Merrick Garland, previous year and accused Gorsuch of being "too extreme".
Just three Democrats crossed party lines to confirm Gorsuch: Sens.
He fills the almost 14-month-old vacancy created after the death of the late Justice Antonin Scalia, who anchored the court's conservative wing for almost three decades before he died unexpectedly in February 2016. Senate Republicans refused to even hold a hearing for Garland, saying a high court replacement should be up to the next president.
Garland never saw a vote.
In perhaps the most notorious opinion of his judicial career, the so-called "frozen trucker" case, Gorsuch dissented against a majority decision supporting the right of a truck driver, caught in an unexpected blizzard, to disconnect his load and drive his rig to shelter.
The Supreme Court still has 13 cases it will hear this term, including a significant religious liberty case looming next week.