Former D.C. Council chairman Kwame R. Brown after his June guilty plea. (Jahi Chikwendiu/THE WASHINGTON POST)

Former D.C. Council chairman Kwame R. Brown was sentenced to one day in the custody of federal marshals and six months of home detention during an emotional Tuesday morning court hearing that punctuated the unraveling of a once-promising political career.

Brown never faced serious jail time — prosecutors and his attorneys were quibbling over how many days, not months, he should serve — but the former public official nevertheless choked up as he apologized to a judge for lying on applications to obtain two bank loans.

Reading from a prepared statement, Brown told U.S. District Judge Richard J. Leon that his errors had not only forced him to resign as council chairman but also inflicted a steeper, more personal, penalty.

“I’m sorry because I have wasted the opportunity to be the most positive example I can be to my children, my family,” said Brown as he faced the judge in a sixth-floor courtroom of the District’s federal court.

The 42-year-old then drew a parallel between his failings and lessons he has taught his young son and daughter about integrity. He drives his children to school, he said, and always halts at two stop signs that are just 25 feet apart, even though many motorists ignore at least one. Brown said he has taught his children that they must obey both signs because “that’s the law.”

“Your honor, I didn’t stop when I was filling out that application,” Brown acknowledged.

Later Tuesday, Brown was sentenced by D.C. Superior Court Judge Juliet J. McKenna to 30 days in jail, which were immediately suspended, for violating a city campaign statute that prohibits cash expenditures in excess of $50.

The son of a well-known D.C. political operative, Brown was considered a political prodigy, winning the council chairman’s job in 2010 at the age of 40. Six years earlier, Brown had become the first person living east of the Anacostia River to win a citywide council seat.

In June, Brown resigned as chairman and pleaded guilty to a federal felony count of bank fraud, admitting he provided false information on applications to obtain loans worth more than $200,000. Prosecutors noted that he faxed one of those applications from his council office in 2005, when he was an at-large member.

Two years later, Brown admitted, he applied for a $55,335 loan to buy a boat by switching a “3” to an “8” on a document to inflate his salary as a consultant from $35,000 to $85,000. He named the boat “Bullet Proof.”

Federal prosecutors asked Leon to sentence Brown, a Democrat who lives in Southeast, to six days in jail to be served over three weekends, followed by three years of supervised release. They said the short jail stint would send a message that Brown had committed a serious crime while acknowledging his acceptance of responsibility and cooperation with their investigation.

Voters “placed their faith in him, in the defendant to follow the law, to protect the integrity and reputation of the District of Columbia and council and to be a role model,” Assistant U.S. Attorney David Johnson said.

A primer on recent D.C. corruption scandals.

Brown’s attorney, Frederick D. Cooke Jr., argued that the judge should spare his client jail time because he had already lost his job and been publicly humiliated. “He has ruined what was once a bright political future,” Cooke said.

Cooke added that Brown did not hesitate to aid federal officials in their investigation, although neither the attorney nor federal prosecutors have detailed the extent of that help. Federal authorities are in the midst of a wide-ranging public corruption probe into a major city contractor’s ties to elected officials and Mayor Vincent C. Gray’s 2010 mayoral campaign.

Leon said he thought six days in jail would serve little purpose but did not think he was legally permitted to sentence Brown to probation without a term of incarceration. He ordered Brown to be placed in the custody of deputy U.S. Marshals until 5:30 p.m., to spend six months on home detention and then serve two years of probation. He must also complete 480 hours of community service.

“Stop at those stop signs; follow the rules,” the judge admonished him.

A few hours after his appearance in federal court, Brown appeared in Superior Court in a charcoal-gray suit, his wrists and ankles in shackles, as two marshals led him into the courtroom for sentencing on the misdemeanor, to which he also pleaded guilty in June.

Asked by McKenna whether he had any comments before she issued her sentence, Brown softly replied “No, your honor.”

In addition to the suspended jail sentence, McKenna placed Brown on two years of probation.

“This is just punishment for his crimes and a deterrent for any such additional conduct,” McKenna said.

Brown was the second council member to resign from office and plead guilty to felony charges this year. Harry Thomas Jr. was sentenced to 38 months in federal prison for stealing more than $350,000 in city funds.

Mike DeBonis contributed to this story.