Lewis, an eight-time Pro Bowl selection, is the biggest name among Under Armour's corps of NFL representatives, which includes fellow Ravens linebacker Terrell Suggs, former University of Maryland and current San Francisco 49ers tight end Vernon Davis and New York Jets linebacker Jonathan Vilma.
Steve Battista, Under Armour's vice president of marketing, said landing Lewis is in line with the company's marketing strategy.
"It's always centered around performance on the field and the top performers on the field," Battista said. "When you look at an A.J. Hawk [the Green Bay Packers linebacker] and a Jonathan Vilma, they are guys who are known for their performances on the field more than anything else. Ray Lewis is definitely in that category."
Lewis, who had previously endorsed Reebok, will wear Under Armour gloves and cleats this season, and his picture is already on billboards on the portions of Interstate 95 that pass the city.
Ira Rainess, Lewis' business manager, said his client's familiarity with Under Armour's products and quality persuaded him to make the leap from Reebok.
"Ray's about performance, and Under Armour's reputation for performance matches up with Ray and what he stands for," Rainess said.
Rainess said Lewis, who is also a spokesman for VitaminWater, isn't overly concerned with any national attention or acclaim stemming from future print and broadcast ads.
"It's what he stands for. That is what is most important to him," Rainess said. "Ray sets an example of hard work on and off the field, and companies that sit down with him are impressed with his vision and what he wants to accomplish."
Lewis was unavailable for comment, as players were off yesterday.
Battista declined to reveal terms of the multiyear deal but said both parties would benefit from the partnership.
"It's great to have him on our team," Battista said.