WASHINGTON - President Donald Trump's appointee Neil Gorsuch jumped right into the fray Monday in his first day hearing cases as a member of the U.S. Supreme Court, asking so many questions that at one point he apologized for talking so much.

The first of the three cases before the justices Monday involved an employment dispute. Gorsuch showed no hint of nervousness sitting alongside his eight new colleagues as he grilled lawyer Christopher Landau over the fine points of a law governing civil service employees.

Landau represented a man claiming he was discriminated against by his employer, the U.S. Census Bureau.

"I apologize for taking up so much time," the black-robed Gorsuch said, sitting back in his high-backed chair and smiling.

The other two cases the justices will hear Monday involve a property dispute and the timing of securities class-action lawsuits.

Gorsuch formally joined the court April 10 after being confirmed three days earlier by the Republican-led Senate over broad Democratic opposition.

The court had its full complement of nine justices, five conservatives and four liberals, for arguments for the first time since the death of long-serving conservative Antonin Scalia in February 2016. Gorsuch restored the conservative majority on the court.

Chief Justice John Roberts welcomed Gorsuch to the court before oral arguments began, wishing him "a long and happy career" in the lifetime job. Gorsuch thanked Roberts and the other justices for their warm welcome.

Gorsuch showed his well-known, heavy focus on the text of statutes in order to judge cases before him. Citing a section of the Civil Service Reform Act, he asked Landau where in the statute does it say federal district courts may hear cases involving both discrimination and civil service claims.

"Looking at the plain language of the statute, just help me with that," Gorsuch said.

One of the lawyers due to argue the second case before the justices Monday will be a familiar face to Gorsuch. Neal Katyal, who served as acting solicitor general in Democratic former President Barack Obama's Justice Department, heartily endorsed Gorsuch's nomination, even testifying at his Senate Judiciary Committee confirmation hearing.

Gorsuch, at 49 the youngest new justice in a quarter century, served for a decade on the Denver-based 10th U.S. Circuit Court of Appeals before Trump nominated him in January.

Trump was able to fill Scalia's vacancy only because Senate Republicans last year refused to consider Obama's nominee Merrick Garland.

The second of Monday's three one-hour oral arguments involved whether a developer can intervene in a lawsuit brought by a property owner against the town of Chester, New York, over its refusal to give him permission to build on his land.

Katyal, who has argued numerous cases before the high court, represented the town of Chester. Republicans backing Gorsuch's confirmation often cited liberal Katyal's endorsement as evidence that the judge enjoyed support across the political spectrum.

Katyal was also scheduled to argue before the justices on April 25 on behalf of Bristol-Myers Squibb Co in a case over out-of-state injury claims.

The third case Monday was a dispute over whether certain securities class-action lawsuits can be barred because they were filed too late.