The longtime treasurer of a volunteer fire department in Loudoun County who admitted swiping more than $645,000 from his organization to pay for personal expenses — including his mortgage, credit card bills and car repairs — was sentenced Friday to a year and a day in prison.

Calling the crime a “colossal, epic steal,” U.S. District Court Judge Gerald Bruce Lee ordered 80-year-old Jerry Keith Cromer Jr. immediately into the custody of U.S. marshals, who led him away as family members looked on. Cromer — the former treasurer of the Aldie Volunteer Fire Department and a longtime resident of the small Virginia town it serves — pleaded guilty in July to theft from an organization receiving federal funds, admitting that he essentially used the department’s treasury as his personal bank account for more than a decade.

“It’s an extraordinary case,” Lee said as he delivered the sentence. “It just was a dual life you were leading, and a false life.”

Although federal sentencing guidelines called for a prison term of 30 to 37 months, the one-year sentence was still somewhat stiff given Cromer’s age. Prosecutors and defense attorneys had not asked that Cromer, who cares for his wife, spend any set amount of time in prison, and they agreed that whatever term he serve should be followed by home confinement.

For his part, Cromer apologized and said he was ready to accept any punishment the judge deemed fit.

“I broke a lot of trust, and I’m ashamed of that,” he said.

Cromer’s crime was lucrative, though it was hardly sophisticated. Prosecutors said Cromer, who had “sole signature authority” on the department’s checks, simply transferred money from department accounts to personal ones, or wrote checks from department accounts to pay his mortgage and Sears, Chase and BP credit card bills.

The theft began in 2000 and continued through September 2012, when an examination of the department’s finances for tax purposes revealed irregularities, authorities have said. Cromer, who had been treasurer since 1995, was then removed from the post, authorities have said.

Assistant U.S. Attorney Mark D. Lytle said in court Friday that some prison time was necessary “to warn those who might be in a similar position of trust.”

“It was a major amount of money to embezzle,” he said.

Shannon S. Quill, Cromer’s defense attorney, urged Lee to be lenient, arguing that Cromer cooperated with investigators and had already begun paying back the money he stole. In court and in filings in advance of the sentencing, she asked Lee to consider Cromer’s personal circumstances. She said Cromer — who served in the Army and ran a family farm in addition to his work at the fire department — was a poor money manager who, along with his wife, amassed almost $100,000 in credit card debt.

“He didn’t see a way out, and then it came to light,” Quill said.

Cromer’s case is among a handful recently brought by federal prosecutors in Alexandria against volunteer fire officials accused of stealing from their organizations. Two officials at the Remington Volunteer Fire and Rescue Department in Virginia’s Fauquier County — William Joseph Stuart and Douglas G. Taylor — pleaded guilty in similar cases in recent months.