Supreme CourtJustice Neil M. Gorsuch took the seat of the late Antonin Scalia a year ago Tuesday, but court watchers say he has staked out a path closer to another conservative icon: Justice Clarence Thomas.

It’s early yet, and Justice Gorsuch has just 40 decided cases under his belt, but in 37 of those he agreed with Justice Thomas, including all 15 cases they both ruled on in the court’s previous term.

For the conservatives who backed President Trump because of the open Scalia seat, there is plenty in Justice Gorsuch’s first year to satisfy them — and to suggest more good things are on the way.

Meanwhile, liberals who feared the Gorsuch nomination, say he has borne out their concerns.

From early judgments in last year’s travel ban case to a gay rights lawsuit out of Arkansas, Justice Gorsuch has found himself part of a triumvirate that includes Justices Thomas and Samuel A. Alito Jr., who was President George W. Bush’s second pick to reach the high court.

“The fact that he is on the Alito/Thomas end of that spectrum, I think you have to say it’s a pleasant surprise,” said Curt Levey, president of the conservative think tank Committee for Justice.

Dan Goldberg, legal director of the progressive Alliance for Justice, said Justice Gorsuch has made even bigger news with his outside-the-courtroom activities.

That included a speech in September at the Trump International Hotel in the District of Columbia to help raise money for a nonprofit scholarship fund backed by conservative bigwigs.

A dinner with Republican senators in January and an appearance with Senate Majority Leader Mitch McConnell at an event in Kentucky added to the criticism.

“Given how he was confirmed, I would have thought he would have been incredibly diligent in being apolitical,” Mr. Goldberg said.

Perhaps no justice in history has been under more scrutiny during his first year, which began after his Senate confirmation on April 7, 2017.

SCOTUSblog evaluated Justice Gorsuch’s questions during oral arguments as “more aggressive” than those of other new justices.

His writing style also has been put through the wringer. The Federalist, a conservative website, said Justice Gorsuch has brought needed wit and clarity to a dreary art. Slate, though, argues that he had a certain flair as an appellate judge but lost it on the high court.

The American Bar Association Journal even wondered whether Justice Gorsuch was meddling with the court’s writing process and speculated that the rookie was the reason for a slow pace of opinions during this term. CNN said Justice Gorsuch was writing more opinions than average.

Analysts are eager to categorize Justice Gorsuch, leading to the comparisons to Justice Thomas.

According to SCOTUSblog’s annual review, Justice Gorsuch has agreed with Justice Thomas 81 percent of the time this term and was in 100 percent agreement with him during the previous year.

“I don’t think I saw a single year where Justice Scalia had a 100 percent agreement with Justice Thomas,” said Carrie Severino, a former law clerk for Justice Thomas and chief counsel for the conservative Judicial Crisis Network.

But one outside adviser to the White House on nominations said not to read too much into the comparisons because there wasn’t much of a difference between Scalia and Justice Thomas in recent years.

The adviser said Justice Gorsuch is focusing on the big issues of government power and who should wield it.

“You can see from his questioning from the bench, when there are matters that come before the court that pertain to administrative agency action, that Justice Gorsuch is thinking very carefully about the scope of an agency’s powers,” the adviser said.

Justice Gorsuch was part of six 5-4 rulings so far and was in the majority on four of those. He wrote the majority opinion for one of those rulings. The case dealt with how Congress intended for attorneys’ fees to be paid after prisoners win civil rights judgments against incarcerators.

All told, he has been part of seven dissents and has written opinions in three of them. One of his more attention-grabbing dissents was in a case that overturned Arkansas’ law against same-sex spouses adding their names to birth certificates when one of them gives birth.

The majority said same-sex couples’ rights were unfairly violated, but Justice Gorsuch, along with Justices Alito and Thomas, said the state law should have been left alone and didn’t clash with previous rulings establishing a right to same-sex marriage.

Justice Gorsuch also made waves last year when he joined a unanimous court in allowing some of Mr. Trump’s travel ban to go into effect, within limits. Justice Gorsuch joined Justices Thomas and Alito in saying he would have gone even further and allowed the full policy to take effect.

The trio criticized their colleagues for a vague ruling, predicting it would be followed by a flood of complicated cases asking what the limits are. They were quickly proved correct, as a new round of court filings across the country made clear.

Josh Blackman, a professor at South Texas College of Law, said he was particularly struck by an opinion that Justice Gorsuch didn’t sign onto.

In February, the court declined to hear a challenge to California’s law requiring a 10-day waiting period to purchase a firearm. Justice Thomas dissented, saying the court should have taken the case, but Justice Gorsuch did not join him.

“I couldn’t tell you why,” Mr. Blackman said. “That one made me very nervous.”

Mr. Goldberg, meanwhile, said he is waiting to see how Justice Gorsuch rules in a case brought by Illinois state employee Mark Janus on whether public employee labor union members can be required to pay dues even when they disagree with the union’s politics.

Mr. Goldberg said there is a clear precedent that unions can require the dues and that the case will be a test for Justice Gorsuch’s vow during his confirmation hearings to respect precedent.

“If he meant what he said, his vote in Janus should be very easy,” Mr. Goldberg said.