Terms of the investment, which was announced Monday, were not disclosed. Forbes most recently valued the Kraken at an estimated $875 million.
"This is something I never would have imagined," Lynch, who played seven of his 13 NFL seasons in Seattle, told CNBC in a statement. "I always dreamed of playing on a professional team but owning one is something special. As I look back on some of my accomplishments...I'm [going to] continue to count my blessings."
Kraken CEO Tod Leiweke told CNBC that Lynch and Macklemore approached the team about becoming investors last summer. The NHL signed off on the deal earlier this month.
"For us, we didn't need additional investors," Leiweke said, "but the thing that attracted us to these guys was their interest in community activism through this organization, and that's a big deal."
Lynch in particular will be a part of the NHL's Hockey Is for Everyone campaign, and Leiweke said Lynch has expressed an interest in shadowing him to see the ins and outs of a hockey CEO's operation.
"He's intrigued with the idea of what's it's like to be an owner and the business side and the financing," Leiweke said.
Macklemore -- born Ben Haggerty -- is a Grammy-winning artist who will add to the franchise's entertainment side.
"I'm a big hockey fan and have watched the team come to life and the fan base grow over the last four years," Macklemore said in a statement. "This investment was a natural one."
Seattle will end its first expansion season without a playoff berth. The Kraken's schedule wraps up May 1.