NEWARK, N.J. — For 20 years, Sharpe James served not only as Newark’s mayor, but as its cheerleader-in-chief, promoting redevelopment as the key to overcoming crime, unemployment, and decay. Retirement, however, finds him scrambling to stay out of prison after a federal jury determined his efforts to revitalize a blighted neighborhood included favoritism to a one-time mistress.

James and the woman were convicted yesterday of corruption charges that could send each of them to prison for about seven years. And while they plan to appeal the verdicts and remain free on bail pending a July 29 sentencing, that is not the end of legal troubles for James.

He still faces a federal trial on charges he used city-issued credit cards to pay for $58,000 worth of personal expenses while he was mayor, including trips with several women other than his wife to Martha’s Vineyard, Puerto Rico, the Dominican Republic, and Rio de Janeiro.

The verdicts add a new dimension to the legacy left by James, who was mayor of the state’s largest city for 20 years until 2006 and took credit for redevelopment that included a pro hockey arena that opened in the fall.

Asked if the conviction eradicates James’s work, U.S. Attorney Christopher Christie said, “I’m willing to bet this will be the first line in his obit.”

“This is a guy who believed the property of the people of the city of Newark was property he could feel free to give to pay off his girlfriend,” Mr. Christie said.

A historian at Rutgers University’s Newark campus, however, said that was overly harsh and took a longer view, dating to the city’s deadly riots four decades earlier.

“Sharpe James was the first post-1967 mayor of Newark to articulate a clear vision for Newark’s recovery from nearly a half-century of unmitigated decline, and that’s more than likely what he will be remembered for,” Clement Price said.

James “reknitted the social fabric of Newark,” Mr. Price said.

And while Mr. Price said he accepted the verdict, it sickened him. “Newark is climbing from under a large shadow because of Mayor James,” he said.

James, 72, was mayor between 1986 and 2006 and also a Democratic state Senator between 1999 and January 2008. Yesterday, he was convicted on all five charges he faced, including fraud and conspiracy, for steering discounted city land to his girlfriend at the time, Tamika Riley, 39.

Riley was convicted on those charges and the eight others she faced, including evading taxes and cheating to obtain subsidized housing assistance for herself.