The biggest housing development in South San Francisco in decades is ready to roll after the South San Francisco City Council voted 4-1 early Thursday morning to approve the project.

The 800-unit, three-building complex will sprout on a patch of city-owned land located along Mission Road — a 5.9-acre site about a 10-minute walk south of the city’s BART station. One of the three buildings will contain 158 affordable units.

Councilmember Rich Garbarino was the sole vote against the project. Testimony and debate lasted five hours with the majority of younger renters generally supporting the project and the majority of older homeowners opposing it.

“It was a generational divide — established homeowners against younger people who are hoping to stay in South City and know they will need more housing,” said Eric Tao, a partner with L37 Partners, which is developing the project with Kasa Partners and the affordable housing builder Bridge Housing.

Opponents said the development would worsen traffic gridlock and ruin South City’s small-town feel.

“This is an old, established bedroom community and nobody likes change, and (many are) afraid of traffic and congestion,” Tao said before the vote.“But I think those fears are unfounded.”

The biggest project South San Francisco has seen in recent decades, it would also have a public playground, a day care center and a market hall with space for local artisans.

The developer hopes to start construction in early 2021.

The debate over the project was closely watched by state housing officials, who were critical when San Bruno rejected a 425-unit housing development last summer.

J.K. Dineen is a San Francisco Chronicle staff writer. Email: jdineen@sfchronicle.com Twitter: @sfjkdineen