He was also an integral part of Harrodsburg's football, basketball and track teams.
"He's a kid that in all three of his sports definitely makes a difference," Yeast said. "You take him off your team, and it certainly cuts down on the options you have."
Because of his success in three sports, Dunn is The Kentucky Advocate Male Athlete of the Year for the 2003-04 high school sports year.
It marks the ninth time this award has gone to a Harrodsburg boy since its inception in 1988.
"It was certainly a pleasure to be able to have the opportunity to coach a kid that is a great talent," Yeast said.
Dunn's talent was evident:
Harrodsburg's all-time leading rusher
* In football, he leaves as Harrodsburg's all-time leading rusher - and the 20th-ranked rusher in state history - with 5,106 yards. He had 1,691 yards and 23 touchdowns in his senior year, and he also punted and returned kickoffs and punts.
"I still remember when he was a freshman and I thought, 'My gosh, I've got to face this kid for four years," said Mercer County football coach Duane Hammons. "Every time he put on the pads he was a threat whether he got the ball or not because you had to pay so much attention to him. You had to scheme your whole defense to stop him."
* In basketball, he was a four-year starter who closed his career with 877 points and 606 rebounds. He averaged 13.0 points, 10.3 rebounds, 2.1 assists and 2.0 steals last season, and he shot 47.6 percent from the field.
"He was a 6-foot center. Probably his ideal position was out on the perimeter, but we had to have him inside," Harrodsburg assistant basketball coach Will Begley said.
* In track and field, he qualified for the state meet in four events for the second straight year. He was third in the Class A boys 100-meter dash and part of a third-place finish in the 800 relay.
"I think Mark's the kind of guy, if you put a tennis racket in his hand, he'd be successful," Begley said.
Dunn proved to be a most valuable player even when he wasn't on the field of play. He became a peer tutor for a challenged student in his school, working with him in one class a day and spending lunch hours and other time with him.
"He spends part of his day with him and works on some of his skills," Yeast said. "He's just a super role model for the kid and socially. That's one of the most important things I've seen Mark do since I've been there."
Dunn has also given his time to Special Olympics. Last winter, he and teammate Travis White traveled to Lexington on a frosty Saturday morning for the "Polar Bear Plunge," a Special Olympics fund-raiser in which participants dive into a pool of near-freezing water.
"He's kind of the class clown"
"He is a kid," Yeast said. "He's still 17, 18 years old, so he likes to have a lot of fun. He's kind of the class clown."
Yeast said that comes through in Dunn's classes, too.
"He's a cross between a teacher's pet-slash-pest," Yeast said. "Either they love him or he drives them nuts."
He even does his part to make sure Yeast and several of his teammates look their best by serving as their barber.
"He's a better person than he is an athlete, because he's not been on the most talented teams for football and basketball, but he's never lost his cool," Begley said.
Dunn made the All-Area football teams in 2001, when he rushed for an area-best 419 yards in one game a season total of 2,234 yards, and 2003, and he was an All-Area basketball honoree this year.
He will play in this week's Kentucky-Tennessee all-star football game at Knoxville, Tenn., and he'll play football at Eastern Kentucky University this fall.
"He's moving to another level, and you're going to swim or you're going to sink, and he knows that, and he's looking forward to the challenge," Yeast said.
"I honestly don't think Mark has even hit his potential yet."