The trial of the music mogul Sean Combs, who is facing charges of sex trafficking and racketeering, is set to begin Monday at Federal District Court in Lower Manhattan.

For up to eight weeks, jurors are expected to hear graphic testimony accusing Mr. Combs, 55, of violence and of coercing several women — including his former girlfriend, Casandra Ventura, the singer known as Cassie — into sex.

The day at court: The selection and swearing-in of 18 jurors, including six alternates, is expected to be completed Monday morning. Then the prosecution and the defense are expected to make their opening statements to jurors, and the first witnesses are set to be called by prosecutors.

The prosecution: Prosecutors are expected to argue that Mr. Combs is a serial abuser of women and the leader of a criminal enterprise that worked to fulfill his sexual desires and cover up his abuse.

The defense: His defense lawyers are expected to argue that the sex between Mr. Combs and the women who are part of the case was entirely consensual, and that the government has painted an unfair picture of Mr. Combs’s businesses and employees.

No video or photography: In keeping with longstanding rules at federal courts, there will be no video or photography from the courtroom.

At the opening of jury selection last week, Judge Arun Subramanian, who is overseeing the Sean Combs case, made an observation about a list shown to prospective jurors that contained the names of celebrities that may come up at trial.

“I read through the people and places list, which is several pages long,” Judge Subramanian said at the beginning of the hearing. “I felt like I was reading an appendix from ‘The Lord of the Rings.’”

It was an unusual moment of levity during a serious criminal case — and a rare glimpse into the candid thoughts of Judge Subramanian, who has been a federal judge for only two years but is presiding over one of the most high-profile criminal trials in the country.

Nominated to the bench by President Biden in 2022, and confirmed by the Senate in March 2023, Judge Subramanian was born in Pittsburgh in 1979, to parents who emigrated from India in 1970.

After attending Case Western Reserve University, he earned his law degree from Columbia in 2004. He began building an impressive legal résumé, with clerkships under two federal judges in New York as well as under Justice Ruth Bader Ginsburg at the Supreme Court. In 2007, he joined the law firm Susman Godfrey, and four years later, at age 31, became its youngest partner.

At Judge Subramanian’s confirmation hearing in late 2022, Senator Chuck Schumer, Democrat of New York, called him a “steadfast consumer protection expert” and said that his cases as a lawyer included defending victims of trafficking and child pornography. Judge Subramanian also developed a specialty in bankruptcy litigation.

In addition to overseeing the Combs criminal case, Judge Subramanian has been assigned the antitrust lawsuit against the concert giant Live Nation, which owns Ticketmaster. In that case, which was filed last year and has a tentative trial date in 2026, prosecutors have called for a breakup of the company, which is by far the largest power in the live entertainment world.

He is also a judge who values efficiency in his courtroom. During jury selection for Mr. Combs’s trial, Judge Subramanian asked the prosecution and the defense to let him know when they needed to take breaks, because if they didn’t, he would “just keep going until we reach the finish line.”

“As you will come to see,” he said, “I’m a machine.”

Judge Subramanian is the first person of South Asian descent to be a judge in the Southern District of New York. “My father grew up in a small village,” he said at his confirmation hearing. “One generation later, his son is sitting before this honorable committee. That is the American dream.”

At a speech last year to Columbia Law alumni, faculty and students, he said that as “the new kid” on the bench, he hosted the first karaoke event in the Southern District’s 235-year history. “I did not know,” Judge Subramanian remarked, “that there was so much enthusiasm for karaoke on the Mother Court.”

The line to get into the federal courthouse in Lower Manhattan this morning for Sean Combs’s trial stretches down the block. At least 100 people — including the news media and members of the public — have been waiting for hours (some overnight) to get a seat inside the courtroom for opening statements. Among those in line: Lil Rod, the music producer who sued Combs last year over allegations of unwanted sexual contact, and his lawyer, Tyrone Blackburn.

A publicist for Sean Combs, Holly Baird, spoke briefly with reporters outside the courthouse. She said he was “upbeat, ready to have his side told in court.”

Sean Combs — also known as Puff Daddy and Diddy — is one of the most successful producers and entrepreneurs in contemporary music. He played a key role in making hip-hop a global cultural force, and helped turn rap and R&B artists like the Notorious B.I.G. and Mary J. Blige into household names.

Rising from middle-class origins in Harlem and suburban Mount Vernon, N.Y., Mr. Combs, 55, willed himself into the music business from a young age. While still a teenager, he appeared as a backup dancer in music videos for Fine Young Cannibals and other acts, and he got an internship at Uptown Records, the label at the forefront of new jack swing and the blending of R&B with rap. He soon became an executive there and showed a rare talent for not only producing hit songs but conceptualizing the overall look and attitude of his acts. By putting himself in their high-budget videos, he made himself recognizable to fans too.

Mr. Combs soon became a star in his own right, with his own label: Bad Boy. As Puff Daddy, he went to No. 1 in 1997 with “I’ll Be Missing You,” which sampled the 1980s band the Police; on MTV’s hit reality show “Making the Band” he played the role — perhaps only slightly exaggerated from real life — of the foul-mouthed, short-tempered label boss who demanded the best from everyone in his circle. At the same time, Mr. Combs was becoming a fixture in the tabloid celebrity media through his bacchanalian White Parties at his Hamptons estate and elsewhere, and, at one point, by dating Jennifer Lopez. At his peak, he made fame itself a form of performance art.

Yet he had also been trailed by various accusations of violence, misconduct and negligence. In 1991, at the very beginning of his career, he promoted a charity basketball game in Harlem where nine young people were crushed to death in a stampede. Five years later, he threatened a photographer with a gun. In 1999 he and his bodyguards beat a rival music executive; later that year, Mr. Combs was arrested after a shooting at a New York nightclub where three people were injured. Still, Mr. Combs largely escaped major consequences. He was acquitted at trial for the nightclub shooting and paid about $750,000 of the $3.8 million in settlements for the wrongful death suits over the basketball stampede.

Those controversies and accusations had little effect on his fame or success in his many business enterprises, which included a popular fashion line and a lucrative deal promoting liquor brands. As recently as two years ago, Mr. Combs was being feted as an industry visionary and a philanthropist.

That reputation began to crumble in late 2023, after a former girlfriend, the singer Cassie, accused him of sexual assault, rape and years of physical abuse. In a bombshell lawsuit, Cassie, whose real name is Casandra Ventura, said that Mr. Combs had coerced her into participating in drug-fueled sexual marathons that he called “freak-offs.”

Cassie’s suit was settled in just one day, with what Mr. Combs’s lawyers have described as an eight-figure settlement. But Cassie’s case led to a federal criminal investigation that resulted in Mr. Combs’s arrest in September on charges of sex trafficking, racketeering conspiracy and transportation to engage in prostitution. Ms. Ventura is expected to be the government’s star witness in the case.

Mr. Combs has pleaded not guilty to the charges, and has strenuously denied the accusations against him. In a recent statement about the government’s indictment, Mr. Combs’s legal team said the accusers were “former long-term girlfriends, who were involved in consensual relationships.” It continued, “This was their private sex life, defined by consent, not coercion.”