That honor is just one of many for the 5-foot-11, 145-pound senior.
Look at Clinger's record over the years and the argument could be made that he deserves a place among Utah's most accomplished prep athletes in history.
He is the only boy to ever win consecutive Nike high school cross-country championships. He holds the freshman, sophomore and senior course state Class 5A records in cross-country and won the state individual 5A title twice.
As he prepares for his final track season, Clinger is the two-time defending 3,200- and 1,600-meter champion.
"Casey has a strong work ethic, a good training plan and some great training partners — Patrick Parker and McKay Johns, who are also All-Americans," Caveman coach Timo Mostert said.
Clinger said he spent most of his youth playing soccer and didn't try running until he was in ninth grade. It didn't take long to discover that he had a talent for distance running.
A typical workout for Clinger and his teammates includes a 7-mile run with two stride laps on the track, team stretching then weightlifting and a core workout. Mostert also believes in speed workouts.
Clinger's longtime teammates Parker and Johns, who will be joining him at BYU, said he has pushed them to be better.
"It's great to run with him," Johns said. "He makes all of us faster. He's a great guy."
Parker said that the Cavemen team, which has been among the best in the country the past few years, are good friends off the track. He also praised Mostert for his passion and expert training regiment, which helps the team stay healthy.
So why is American Fork among the best high school distance teams in the nation?
"We get some of our previous all-state and all-American runners to come back and visit with the team during the summer," Mostert said. "There has been a bit of continuity in our success, so the younger guys learn from the older boys, and our traditions and expectations get passed down. We've been blessed with great team captains over the past decade or so."
Clinger's discipline also seems to pay off away from the track. The Gatorade Award is not just about athletics. The American Fork star runner is an Eagle Scout, boasts a 4.0 grade-point average and volunteers at the Utah State Developmental Center, which assists people with intellectual disabilities.
Clinger said that he plays both the electric and acoustic guitar for fun, often jamming with his brothers.