Not every item in Chief Judge Dennis Jacobs’s chambers is government-issue office supply. Take, for instance, the bronze statuette of a banana peel. The peel — cause of slips and falls in cartoons and comics — serves not only as a paperweight but as an object of meditation.

“It reminds you of what can happen if you’re not careful,” Judge Jacobs, the new ranking active judge of the 2nd U.S. Circuit Court of Appeals, said in a recent interview.

He is a careful judge. Legal observers should take note when Judge Jacobs disagrees with his colleagues: In recent years, his dissents have found a friendly reception at the U.S. Supreme Court.

Widely recognized as one of the more conservative jurists on the 2nd Circuit, Judge Jacobs, 63, became chief judge when his predecessor, Judge John Walker, took senior status three weeks ago.

The job of being chief judge goes to the most senior judge on the court under the age of 65. As chief judge, his new administrative responsibilities vary from arranging the judges on the three-judge panels that hear appeals to serving as the presiding member of the council that hears allegations of judicial misconduct, the circuit executive, Karen Milton, said.

The administrative duties of particular challenge to the 2nd Circuit now include a backlog of immigration appeals and assisting with the renovation of the historic courthouse at 40 Foley Square, which the 2nd Circuit left at the end of last term.

Judge Jacobs’ demeanor is marked by a certain collegiality toward the lawyers who argue before him. As he hears cases, he often rocks back and forth in the wide-backed chairs of the Daniel Patrick Moynihan U.S. District Courthouse in Manhattan, where the 2nd Circuit currently meets.

On a recent panel that included Justice Sandra Day O’Connor as a visiting judge, Judge Jacobs appeared nonplussed in the company of the distinguished guest. Devoting his attention to the 12 attorneys who came before him, he did not cast a single deferential glance to where the former Supreme Court justice sat.

Before becoming a judge, Mr. Jacobs litigated at Simpson Thacher & Bartlett, where he spent his 22-year career handling complex cases involving such issues as reinsurance and environmental clean-up.

One of Mr. Jacobs’s early legal feats was to force Muhammad Ali and Earnie Shavers into the ring at Madison Square Garden, the head of the litigation department at Simpson Thacher, Barry Ostrager, recalled in a recent telephone interview. Mr. Ostrager said he and Mr. Jacobs argued in state and federal courts that the two boxers, who sought to avoid the New York fight, were reneging on their contracts to Madison Square Garden. The cases were settled and the two litigators eventually watched from ringside seats as Mr. Ali won the grueling bout, Mr. Ostrager said.

A New York native, Judge Jacobs decided on a career in the law when he was 26, leaving behind a teaching job in English at Queens College.

Dressed in shirtsleeves and a tie even on Columbus Day, Judge Jacobs often plays classical music while working in his chambers, although he said he usually restricts himself to “second-rate music” because he finds the best symphonies too distracting. He enjoys a good read and his bookshelves contain not only the required case law but the works of poets from Cavafy to Yeats. Judge Jacobs is quick to praise well-written prose when it comes his way.

Of a colleague’s decision, Judge Jacobs wrote last year: It is “learned and witty, often at the same time; it is a crackling good read by any standard of law or letters.”

His praise appears in an opinion scrutinizing a Vermont law placing a cap on campaign contributions and expenditures. His concerns that the law was at odds with the First Amendment prompted his dissent from the 2nd Circuit’s decision not to review the case as an entire circuit. The Supreme Court took up those concerns — shared by several other circuit judges as well — and struck down the law as unconstitutional last term.

The Supreme Court also echoed Judge Jacobs’s reasoning in 2001. The judge found that a school in Milford, N.Y.,was not allowed to bar a local Good News club from using the school’s facilities which other groups use. The Supreme Court, in a decision written by Justice Thomas, arrived at the same conclusion.

Nominated in 1992 by President George H.W. Bush and once involved with the Federalist Society, Judge Jacobs’s reputation as being one of the more conservative members of the 2nd Circuit remains strong, according to the anonymous comments of attorneys posted in the “Almanac of the Federal Judiciary.”

In decisions he wrote in a sex-discrimination lawsuit against Vassar College and in a securities fraud case against Merrill Lynch, Judge Jacobs sets high hurdles for plaintiffs. But legal observers qualify his conservative reputation by pointing to decisions in which Judge Jacobs expressed skepticism of the discretion that prosecutors use. Last month, a decision he wrote overturned the prerogative that prosecutors had to hold a defendant’s car as evidence. Now, prosecutors must get permission from a judge.

When Judge Jacobs was confirmed to the bench he filled the opening that Thurgood Marshall had once held, he said.