Taking his seat as the nation's highest jurist, Chief Justice John G. Roberts (search) seemed comfortable and confident as the court's 2005-2006 session began Monday.

Sitting atop the same leather chair used by his mentor, the late William H. Rehnquist (search), Roberts promised to ensure equal justice. Roberts is no stranger to the high court. As an appellate lawyer, he argued three dozen cases before the court, and is familiar with his colleagues who previously sat in judgment of him.

But the new chief's first day didn't offer the most exciting docket. The court heard arguments in IBP Inc. v. Alvarez and Tum v. Barber Foods, companion cases that asked the court to decide whether employees should be compensated for the waiting or walking between mandatory activities.

Afterward, the court also heard arguments in Wagnon v. Prairie Band Potawatomi Tribe, a case about an Indian tribe's assertion that a state tax levied on an off-reservation gasoline distributor that sells to a gas station on the reservation is unlawful.

Roberts welcomed new lawyers to the Supreme Court bar, and perhaps gave them a moment of shivers when he asked a question that made reference to their potential impact on the court.

Referring to Kansas' law, changed in 1995 to place the gas tax burden on distributors rather than the Indian tribe, Roberts asked Theodore Olsen (search), former U.S. solicitor general and now an attorney representing the state of Kansas, whether the state had changed its law on the advice of "some bright young lawyer," suggesting the court would frown on such tactics.

But Roberts, 50, politely and intently listened to the attorneys presenting their cases. He appeared at ease and peppered the advocates with several questions while appearing in command of the facts.

Even with a seemingly festive and formal first day that presented Roberts in a bright light, legal experts say it could take years to fully understand the chief's judicial philosophy.

"I think John Roberts knows where he's coming from and is more likely from the very start to find his footing. But still it takes more than a small sampling of cases before you have really a cross section that tells you where he will be," said Harvard law professor Laurence Tribe.

The court began its new session around 10:30 a.m., with Justice John Paul Stevens (search) ushering in the new term with a remembrance of Rehnquist.

Saying the court would miss Rehnquist's warmth and leadership, Stevens noted that the flags in front of the court, which have been flying at half-staff since the late chief's death on Sept. 3, would be raised to full height on Tuesday. He also commemorated the late justice by saying Rehnquist "led us by examples of excellence rather than by fiat."

He then welcomed Roberts to the court, and thanked Congress for enabling the new chief to be installed by the opening session.

Earlier in the morning, Stevens led the formal investiture of Roberts, a ceremony that mimicked one held at the White House last Thursday except that the press cameras were absent this time.

In attendance at the private ceremony were Roberts and his immediate family, President Bush, Senate Judiciary Committee Chairman Arlen Specter, R-Pa., and Attorney General Alberto Gonzales, among others. Gonzales presented to Roberts a poster-sized, ivory-colored document that Bush signed stating his intent to nominate Roberts to be chief justice. It was unrolled and read aloud.

Stevens, the court's eldest member, led the oath of office.

"It is a pleasure to extend to you a very warm welcome as chief justice of the United States," Stevens, 85, then told his new colleague.

Afterward, Stevens and Roberts exited the court and walked down the marble stairs together. Near the bottom, Stevens lost his balance on the steps, but recovered quickly as Roberts grabbed his arm to help steady him.

Along with being on opposite ends of the court's age spectrum, Stevens and Roberts share other distinctions inside the court. As the bench's eldest member, Stevens will assign opinions when he votes in the majority and Roberts votes with the minority. If Roberts' voting record is similar to that of his predecessor Rehnquist, he and the more liberal Stevens are likely to find themselves frequently in disagreement.

But that should not bode ill for Roberts, who while the court's newest and youngest member, was held in high regard among the justices as an attorney for the government and private clients. Stevens was reportedly quite pleased when Bush first nominated Roberts to the bench.

While on the court's steps, the two justices chatted amiably as they posed for photographs, the elder justice breaking into a laugh at times. Stevens then stepped aside as Roberts' wife, Jane, and their two children, Jack and Josie, emerged from the building.

The fidgety 4-year-old, Jack, already a press darling for his impromptu jigs during formal occasions, tried several times to make a break from his mother's grasp before freeing himself and flying toward his father. Roberts caught and swooped up his son in the day's most memorable photo opportunity.

Outside the courthouse, Roberts and his family were cheered by about three dozen members of Bound 4 Life, an anti-abortion group that has been a steady presence in front of the court. Many of the group's teen to young adult members had taped the word "life" over their mouths, while others sang religious songs and lifted their arms in the air.

Some members called out to Roberts directly, saying, "We love you," and "We're praying for you." Roberts maintained his by now familiar, steady grin, and only his wife, a pro-life attorney, waved at the group.

Most of the spectators at the court were not there to protest or applaud, but to be present for an historic day.

The Barger family of Meade County, Kan., was vacationing in Washington, D.C., and decided to attend the Supreme Court's opening day as an educational experience for their teenage son.

"[Roberts] is going to affect the way the country is run for the next 40 years," said Keith Barger, a 17-year-old high school student. "It was interesting to see how he acts on his first day."

Barger said he was impressed with the new chief justice. "He wasn't trying to make too much of a scene."

FOX News' Megyn Kendall contributed to this report.