Sharpe James, the charismatic and combative mayor of Newark for 20 years who presided over a downtown resurgence and pressed to upgrade its blighted neighborhoods, but who was later convicted in a corruption scandal stemming from his time in office, died on Sunday in West Orange, N.J. He was 89.

His death, at an elder care facility, was confirmed by his son John Sharpe James, a former Newark city councilman.

In public, Sharpe James was a colorful, affable cheerleader for his city during his record five terms as mayor, from 1986 to 2006. Behind the scenes he was a cold-eyed political chief adept at punishing rivals and rewarding supporters to retain power.

Suspicions of corruption began in the 1990s with well-publicized federal investigations of allegations that he had used his office to finance an extravagant lifestyle that included a Rolls-Royce and a 54-foot-long yacht. He was not charged with crimes, however, until 2007, a year after he decided not to run for a sixth term, and was found guilty by a federal jury in 2008 of conspiring while mayor to sell city-owned properties to a former companion at a fraction of their value.

Mr. James won his fifth term in 2002 after his only tough re-election battle. He defeated Cory Booker, a fellow Democrat and a City Council member at the time, with 53 percent of the vote in a nonpartisan contest. It was by far the smallest victory margin in Mr. James’s four re-election contests.

Mr. Booker was preparing to face off against Mr. James again in 2006 when Mr. James decided against another run. Mr. Booker won the election, and then a second term, before being elected to the United States Senate in 2013.