"We are devastated by the news of Chris Kyle's death," William Morrow executive editor Peter Hubbard said in a statement. "It was an incomparable honor to help share Chris's story of service and faith with the world. Chris was a hero as much on the home front as on the battlefield -- a man who dedicated his life in recent years to supporting veterans and donated the proceeds of American Sniper to the families of his fallen friends. He deserves our deepest respect. Our prayers are with his family and the entire military community. He will never be forgotten."
Kyle was also an advocate for his fellow service members suffering from PTSD, creating a foundation to help with their treatment.
In an interview on Guns.com, he discussed the difficulty troops face coming home from combat zones.
"All of a sudden you don't have no identity," he said "And you have to learn a whole new way to act."
Brandon Webb, a fellow SEAL who knew Kyle from SEAL Team Three then later when Webb was an instructor at the SEAL sniper course, called him a "larger than life Texan" and said he "will go down in history as one of the world's most accomplished military snipers, right next to Carlos Hathcock, and Lyudmila Pavlichenko."
"Chris was very adamant about supporting veterans issues," Webb said. "This was an subject close to his heart, and not many in our community realize how much of his time was spent on veterans' causes. ... Chris will be remembered as a great American Hero, and another friend lost but not forgotten."
Cox said Kyle's wife Taya and their children "lost a dedicated father and husband" and the country has lost a "lifelong patriot and an American hero."
"Chris Kyle was a hero for his courageous efforts protecting our country as a U.S. Navy SEAL during four tours of combat. Moreover, he was a hero for his efforts stateside when he helped develop the FITCO Cares Foundation. What began as a plea for help from Chris looking for in-home fitness equipment for his brothers- and sisters-in-arms struggling with Post Traumatic Stress Disorder (PTSD) became an organization that will carry that torch proudly in his honor," Cox said in a statement.
The fatal shooting comes after week filled with gun-related incidents, as the national debate heats up on what to do about gun violence.
In the past week, a teen who participated in President Obama's inaugural festivities was shot to death in Chicago, a bus driver was fatally shot and a 5-year-old was taken hostage in Alabama, and a Texas prosecutor was gunned down outside a courthouse.
The Associated Press contributed to this report.