Norris, 43, pleaded guilty in U.S. District Court in Baltimore to conspiring to misuse money from a supplemental city police fund and lying on tax returns.
The former city police commissioner and Maryland state police superintendent is now a convicted felon and could face up to a year in prison at sentencing, scheduled for June 21.
His attorneys are expected to ask that he receive a sentence of probation or home detention.
The federal charges against Norris grew from an off-the-books police expense account, which court records show Norris used to pay for extramarital encounters with several women and to satisfy an apparent taste for the good life.
His extravagant splurges included shopping trips to Coach and Nordstrom, outings with friends at pricey hotel bars, and steak dinners at Smith & Wollensky in New York and Flemings in the .
Maryland U.S. Attorney Thomas M. DiBiagio said at a news conference that Norris' conviction was a "reminder of the embedded corruption here, and the emerging resolve not to look the other way."
"We deserve better," DiBiagio said. "We deserve public officials who are both effective and honest. The only way to get from here to there is a policy of zero tolerance [for corruption], backed up by an unyielding commitment and intractable belief that the rules apply to everyone."
In a 14-page statement of facts detailing the case, federal prosecutors said that evidence presented at a trial would have shown that Norris had taken steps to disguise his personal spending as being for legitimate department business and was wary of detection.
After a member of the department's legal office raised concerns about the spending pattern with internal affairs, Norris complained that the employee had "gone outside the family," according to court records.
When Norris worried that surveillance cameras at the Hyatt Hotel in downtown Baltimore could have captured him going into a hotel room with an unidentified woman in December 2001, Norris' then-chief of staff John Stendrini and another department employee went to the hotel to look for video cameras, the court papers show.
Stendrini was charged along with Norris in a federal indictment in December and is scheduled to stand trial in June. His attorney did not return a phone call yesterday seeking comment.
In court, lawyers representing Norris said that if his case had gone to trial they would have disputed some of the government's allegations, which listed 34 instances of improper activity or spending by Norris in connection to the supplemental police account, originally created as a Depression-era charity fund.
But defense attorney David B. Irwin said the disagreements were minor and did not change the outcome of the case.
Norris stood stiffly throughout the half-hour court hearing, his hands folded in front of him, and said little beyond answering questions from U.S. District Judge Richard D. Bennett about whether he understood the charges against him, his possible punishment and the implications of his felony conviction.
"Did you in fact commit the offenses as summarized by the government?" Bennett asked Norris at one point.
"As summarized," Norris replied.
Asked by Bennett what his plea was to the conspiracy charge and to the tax violation, Norris answered twice in a low voice, "Guilty."
The plea deal between Norris and federal prosecutors, first presented to Bennett late Friday and finalized over the weekend, could change. The U.S. Supreme Court is considering a constitutional challenge to the anti-corruption statute that prosecutors relied on in charging Norris with conspiring to misuse money from the police supplemental account.
If the Supreme Court rules that the statute is unconstitutional on its face, Norris would be allowed to withdraw his guilty plea to that charge. His conviction for filing a false tax return would stand, although his potential punishment would drop - from a prison term of six to 12 months to a sentence of up to six months.
The high court is expected to rule by June. Norris will not be sentenced until that ruling has been issued, Bennett said.
Irwin told reporters outside the courthouse that Norris agreed to the plea deal now because he wanted the case ended.
"He made the decision that a long, drawn-out trial would bring too much pain to his family, his friends and the city of Baltimore," Irwin said. "Now, he'll try to pick up the pieces with his family and put this behind him."
Norris, who has a young son, has been living in Florida in recent months.
The barrel-chested Norris came to Baltimore in early 2000 from his hometown of New York and was quickly yoked to Democratic Mayor Martin O'Malley's pledge to reduce crime. Less than three years later, Norris was chosen by Republican Gov. Robert L. Ehrlich Jr. to serve as superintendent of the Maryland State Police. Norris resigned that post in December, on the day he was indicted in federal court.
Ehrlich had indicated that Norris could have resumed his duties if he had been cleared. But yesterday, the governor said he would submit the name of acting state police Superintendent Thomas E. Hutchins to be the permanent agency head.
Regarding Norris, Ehrlich said: "Obviously during his brief tenure with us, about a year, he was a very strong leader. Somewhat controversial in the way he did business, but he produces results, which was very impressive to me and our senior staff."
"What had occurred in prior years, during his tenure in Baltimore City, was the focal point here [in the federal court case], and it's a shame for all concerned," Ehrlich said.
O'Malley said yesterday that he had mixed emotions about the outcome of the case and said he was "embarrassed and disappointed" that the abuse of the spending account had occurred during his administration.
Court papers filed yesterday by Assistant U.S. Attorneys Steven H. Levine and Jason M. Weinstein portray Norris as putting the supplemental police account to personal use within months of taking over as the city's top officer in spring of 2000.
The use of the fund ended about August 2002, when articles in The Sun disclosed that the account was being used to pay for items that did not directly benefit the department or its officers.
The extent of the abuse was made plain yesterday in court records, which listed expenditures such as $579 worth of alcohol from Wells Discount Liquors that was delivered to Norris' home. Also listed was money that Norris used to buy gifts for three unidentified women just before Valentine's Day 2001 from the lingerie store Victoria's Secret.
Prosecutors said one of the gifts, a black robe, would have been introduced as evidence at trial.
Court records also show that Norris' personal liaisons and spending habits sometimes overlapped with his workday. Prosecutors said members of Norris' protection unit and "several women would have testified that Mr. Stendrini allowed Mr. Norris to use his apartment ... for romantic encounters - referred to by Mr. Norris as 'naps' - often during the workday, and sometimes several times per day."
In one instance, a woman referred to in court papers only as "Female #1" said she traveled to New York City and stayed with Norris at the W Hotel from July 11, 2001, to July 13, 2001. The hotel bill, of $918.70, was paid for from the supplemental account.
In addition to the romantic encounter, Norris also apparently was job shopping - New York Mayor Michael R. Bloomberg's office has confirmed for prosecutors that then-candidate Bloomberg met with Norris on July 12, 2001, about returning to a possible job with the New York City Police Department.
Sun staff writer David Nitkin contributed to this article.