Turner, who sought to expand economic opportunities, faced King, who had pledged to fix city finances, in a runoff after a November election failed to produce a winner.
Turner, a powerful Democrat in the Republican-dominated state legislature, was elected to a two-year term in office of one of the fastest-growing major U.S. cities, whose fortunes are closely tied to an oil industry that is currently slumping due to low prices for crude.
With more than 210,000 votes cast, Turner claimed victory with 51 percent to 49 percent for King, who conceded defeat.
Turner praised his opponent “for making this a very competitive race and a very issued-oriented race.”
“It’s going to take all of us, working together, to make this a great city,” he said.
King encouraged the people of Houston to support the incoming mayor, adding that he had offered Turner his assistance in facing tough challenges.
“I look forward to talking with him in the weeks and months to come on how we all can work collectively,” Turner said.
The race had been a dead heat throughout the campaign, with the focus on a city deficit that looks set to expand, ballooning pension costs for city employees and a lag in services for the quickly growing population of 2.5 million people.
Turner, backed by public sector unions, supported the Houston Equal Rights Ordinance (HERO) which bans discrimination based on gender identity and sexual orientation, protections not guaranteed under Texas law.
HERO was rejected by voters in November after a campaign by opponents largely focused on concerns about the use of public bathrooms by transgender people.
King, a Republican lawyer and businessman, called himself “unapologetically moderate”. He said the HERO debate created unnecessary division.
Mayor Annise Parker, a Democrat and the first openly lesbian mayor of a major U.S. city, was prevented by term limits from seeking re-election.
The energy industry, which accounts for about 40 percent of Houston’s economy, has sent the fortunes of the city on a roller coaster ride for decades.
Since 1969, Houston has been one of the most successful major U.S. cities in terms of per capita personal income growth. Since about 2003, about 650,000 jobs have been created in the Houston area, according to the University of Houston.