Watt began designing the shoe -- the JJ IV Valor -- before he signed with the Cardinals on March 1 and had Tillman's widow, Marie, assist through the design and development process "to ensure the end result would be a meaningful and worthy tribute to her late husband," according to a release.
Reebok will donate $10 to the Pat Tillman Foundation for each pair of shoes that is sold up to $10,000, and Watt will donate all of his personal proceeds from the shoe to the Pat Tillman Foundation.
During his introductory video conference after joining the Cardinals, Watt said he has "long been a fan of" Tillman.
"What he stood for, who he was and everything about his legacy is unbelievable to me," Watt said. "So, to be here, to be walking the same halls that he walked and to see his locker today was special for me."
Watt decided to honor Tillman and work with Pat Tillman Foundation as part of his annual act of giving back to the military. Watt has tried to do "at least" one thing each season with the military to show his appreciation for its service.
"I truly believe that they're the ones that deserve the amount of praise and fame that we as athletes get because they're the ones that protect us and protect our freedoms and give us the opportunity to play this game for a living," Watt said.
The shoe will be two different shades of grey -- Trek and Boulder -- and Rich Red. There will be a camouflage design on the heel as well as "PT40" inscriptions, a Pat Tillman Foundation sock liner, and a commemorative hangtag.
The shoe will be available on Thursday.
"J.J. exemplifies our values of scholarship, service, humble leadership and impact," Pat Tillman Foundation CEO Dan Futrell said. "In J.J., we see someone who shares Pat's passion for living, his tenacity on the football field and off through his deep investment in making a difference in his community and on a global scale. We're grateful to partner with him and Reebok on this latest release."