The N.F.L. on Thursday announced that the Washington Football Team would pay a $10 million fine to the league after a yearlong investigation into reports of the club’s rampant culture of sexual harassment perpetuated by managers and executives under the ownership of Daniel Snyder. The team also must reimburse the league for the cost of the investigation.

Snyder will remove himself from day-to-day business operations of the club through at least mid-October, ceding that control to his wife and new co-chief executive, Tanya Snyder. Daniel Snyder, though, will attend games and continue to work on searching for a new team name and a new stadium. Vestry Laight, a firm that works with companies to address misconduct, which was already retained by the team, will provide the league with updates on the team’s human resources practices for the next two years.

Roger Goodell, the league’s commissioner, “concluded that for many years the workplace environment at the Washington Football Team, both generally and particularly for women, was highly unprofessional,” the N.F.L. said in a statement. “Bullying and intimidation frequently took place and many described the culture as one of fear, and numerous female employees reported having experienced sexual harassment and a general lack of respect in the workplace.”

The penalties are some of the harshest levied against an N.F.L. team and conclude an investigation into allegations of sexual harassment and abuse by men in the team’s front office dating to 2004. Beth Wilkinson, a lawyer based in Washington who led the investigation, shared her findings in an oral presentation that formed the basis of the league’s decision to penalize the team.

“We are incredibly remorseful and incredibly sorry, and we want everyone to be treated with dignity and respect and professionalism,” Daniel Snyder said in an interview on Wednesday.

“I’m mortified to think that’s happening in our building and our business,” Tanya Snyder added.

Nearly 150 current and former employees of the football club were interviewed as part of Wilkinson’s investigation into reports of misdeeds that were detailed in several Washington Post articles last year, as well as reports in The New York Times in 2018 about abuse of cheerleaders. In addition to several incidents of inappropriate treatment of female office workers and cheerleaders by men employed by the franchise, The Post reported that two women had accused Snyder, 56, in separate episodes of harassment dating to 2004. He has denied those allegations.

Snyder also reached a financial settlement in 2009 with a female former executive who had accused him of sexual misconduct during a trip on a private jet. He has denied any wrongdoing.

The N.F.L. released only a brief summary of the team’s toxic internal culture, not a full accounting of allegations, so it is unclear how deep the dysfunction went.

Lisa Friel, the N.F.L. Special Counsel for Investigations, said that Wilkinson was not asked to verify the accuracy of any allegations, or produce a written report of her findings to preserve the anonymity of the witnesses.

“We felt it was best due to the sensitivity of the allegations and the requests for confidentiality,” Friel said, adding that a written report might have given away the identity of some of the employees.

Snyder has conceded that he was too lax in his management of the team over the years, leaving much of the day-to-day running of the club to Bruce Allen, the former team president who was dismissed at the end of 2019 after a decade on the job.

“I appreciate the people who came forward and intend fully to implement all of the recommendations coming out of the investigation,” Daniel Snyder said in a statement released Thursday.

Lisa Banks and Debra Katz, lawyers who are representing 40 former team employees, said Wilkinson’s investigation “substantiated our clients’ allegations of pervasive harassment, misogyny and abuse.” They said the N.F.L. was protecting Snyder by ignoring their requests to make Wilkinson’s findings public. The $10 million fine, they added, “amounts to pocket change” for the club.

“The N.F.L. has effectively told survivors in this country and around the world that it does not care about them or credit their experiences,” they said in a statement. “Female fans, and fans of good will everywhere, take note.”

The allegations of widespread harassment within the Washington franchise have been acutely embarrassing for the league, which during the past two decades gained a reputation that it had failed to adequately reprimand players, coaches, staff and team owners who were accused of harassing or assaulting women.

The team also decided to drop its nickname and logo last July after years of criticism from people who considered it a racist slur against Native Americans and of threats from major corporations to end sponsorships. The team is reviewing new names and logos.

In the past year, Snyder also battled publicly with three longtime shareholders. Their boardroom brawl included dueling lawsuits, accusations of the smear campaigns and bullying.

Months before the investigation into the leadership of the team and the conduct of its employees was completed, the league’s owners endorsed Snyder by unanimously voting to allow him to add $450 million of new debt so he could purchase the 40 percent of the team that he and his relatives did not already own.

The fine against the Washington franchise for failing to properly manage its staff is the first financial penalty against a team in a sexual harassment case since Jerry Richardson was fined $2.75 million for making racist comments and sexually harassing female members of his staff while he was owner of the Carolina Panthers. The league fined Richardson after he had reached an agreement to sell the team in 2018 for $2.2 billion.

The N.F.L.’s penalizing of Snyder fell short of suspending him. Only a handful of owners have been suspended, and typically because they were personally charged with crimes. Edward J. DeBartolo Jr. of the San Francisco 49ers was suspended for a year and fined $1 million after he pleaded guilty to one felony charge of failing to report an alleged extortion attempt by the then-governor of Louisiana, Edwin Edwards.

Jim Irsay, the owner of the Indianapolis Colts, was suspended for six games and fined $500,000 after he pleaded guilty to a misdemeanor count of driving while intoxicated following his arrest after a traffic stop in 2014.

After the allegations of sexual harassment became public last summer, Snyder fired nearly every front office executive. He has tried to revive the club’s tattered image by hiring new executives, including Jason Wright, the N.F.L.’s first Black team president, and several women. A coed dance team will perform on game days, replacing the cheerleading program, which had been overseen by one of the since-fired executives who had been accused of sexual harassment.

Snyder said he would adopt the recommendations put forth by Wilkinson, which include the detailed development of protocols for “victims to report anonymously and without fear of retaliation” any misconduct and the implementation of regular anti-bullying, discrimination and harassment training seminars.

Fatima Goss Graves, chief executive of the National Women’s Law Center, said that none of the recommendations can prompt change without the release the investigation’s findings.

“There is no reason to issue a significant fine without giving a full explanation of why,” she said. “It is hard to have meaningful accountability without transparency when the allegations go to the very top of the organization.”

Kim Gandy, the former chief executive of the National Network to End Domestic Violence and a one-time adviser to the league, questioned whether $10 million is significant enough.

“The fine represents only 2 percent of last year’s revenue, and less than three-tenths of 1 percent of the team’s value,” she said.

In the interview this week, Snyder said he and his wife are down to a few dozen options for new names for the team and that a location for a new stadium will be chosen in about six months.

Despite its rebuke of the Washington team, the league as a whole continues to be plagued by claims of harassment, not just in ownership circles, but among players and coaches. “We will review our own policies and practices,” the league said Thursday.