Langford, 53, is a former casino dealer and Atlantic City school board member who served as mayor from 2002 to 2005 before being defeated by Bob Levy.
Langford topped a field of three candidates with 7,271 votes. He defeated Republican John McQueen, a former police dispatcher who ran on an alternative energy platform and got 1,001 votes, and independent candidate Joseph Polillo, a city licensing inspector who got 2,448 votes.
Levy gained national headlines last year as Atlantic City's "Missing Mayor" after dropping out of sight for two weeks, then resigning when he admitted lying about his Vietnam War service to fatten his veteran's benefits check.
Langford will take office as soon as the county clerk certifies the result of the election, which could come by the end of the week. He would have to run in a Democratic primary next June to be nominated to seek a full four-year term in the Nov. 2009 general election.
While the unexpired term is short, the impact could be huge. Atlantic City is heading for its second straight year of declining casino revenues after seeing them go up for 28 straight years.
The city's 11 gambling houses are laying off employees, and customers are fleeing to slots parlors in Pennsylvania and New York. Things got so bad that a total smoking ban in the casinos was put off for at least a year, so as not to hurt the casinos' finances even more.