Company officials sought the city's support as they planned to double the size of the Locust Point campus. Activists, including members of Occupy Baltimore, protested the deal, saying the $1 billion international athletic wear brand does not need financial assistance from the cash-strapped city.
Council members voted unanimously and without discussion to approve the benefit, known as tax increment financing, for the project. The deal allows the city to issue bonds to pay for infrastructure improvements on and around the campus, a former Procter & Gamble factory. The city would use the proceeds from Under Armour's property taxes to pay off the bonds.
Company officials have said they hope to hire as many as 500 workers over the next 10 years as the firm expands.
In the first phase of the project, expected to be completed next year, the company plans to build an 80,000-square-foot office building and a retail outlet. By 2016, Under Armour intends to expand the three largest buildings on its campus and construct an 800-space parking garage.
The company eventually hopes to build a 255,000-square-foot office building.
Under the deal approved by the council, city-issued bonds could fund improvements to Under Armour's campus and the surrounding area, including upgrades of streets and the waterside promenade. The company also wants to construct athletic fields and a biking and walking trail that would connect to Key Highway.
Under Armour, founded by Marylander Kevin Plank, moved to Tide Point in 1999. The company has grown exponentially since then and last year purchased the complex on the southern shore of the Inner Harbor.
Baltimore Sun reporter Luke Broadwater contributed to this article.