The former NFL linebacker, who joined Donald Trump Jr. on a hunting trips just weeks ago, was confirmed dead by his hunting gear company, KUIU, on Wednesday.
"We are shocked and saddened to announce the tragic passing of KUIU founder Jason Hairston. His legacy lives on in KUIU’s spirit of relentless innovation," the company said on Twitter.
The company later revealed on its website that Hairston took his own life.
"He is survived by his wife Kirstyn and 2 children," KUIU wrote. "The family has requested that donations be made to support CTE-related research at the Boston University Concussion Legacy Foundation in lieu of sending flowers."
Trump Jr. also took to Instagram to express condolences for his friend shortly after his passing, calling Hairston "an inspiration to all outdoorsmen and women for generations to come."
"Jason, I have no words. I will always remember our adventures and sharing a campfire with you. They will be some of my fondest experiences in the outdoors," Trump Jr. said in his post. "You were and will continue to be an inspiration to all outdoorsmen and women for generations to come. Thanks for the friendship and the memories buddy. I’m going to miss you. R.I.P."