The Crystal Lake, Ill., native's phone rang, and Heesch had to walk out of the room so he could hear who was on the other line.
It was the Cubs.
"I ran downstairs and my dad had his hands up, screaming that I was drafted by the Cubs, and I said, 'Yeah, I know, I'm on the phone with them right now,'" Heesch said. "To finally hear, 'Hey, we're going to Draft you.' And to hear, 'The Cubs pick so-and-so,' and it's your name ... it's unbelievable."
Heesch, a 6-foot-5, 245-pound left-hander, grew up in the Chicago area but didn't choose a favorite team until he was about 8 years old. His father was a White Sox fan. Heesch chose the Cubs.
Dad was still proud.
"I could have been drafted by anybody and he would've been thrilled," Heesch said.
Heesch is more than just a hometown boy who prepped at Prairie Ridge High School.
He went 9-3 with a 2.21 ERA in 122 1/3 innings at South Carolina-Beaufort this season after transferring from Illinois-Chicago. He also had 118 strikeouts in 122 1/3 innings while walking only 13, and was named second-team NAIA All-American.
South Carolina-Beaufort head coach Bryan Lewallyn, whose father, Dennis, is the Cubs' Minor League pitching coordinator, said in a statement that Heesch's success stems from his work ethic.
"When he got here from UIC, he was at 81-82 [mph] with no breaking ball, and he's done everything that was asked of him and more," Lewallyn said. "He has turned himself into the guy that he is."
Heesch said he's been referred to as a "bulldog" on the mound, and threw five complete games this season, including one shutout. He has three pitches -- a fastball that sits around 90 mph, a slider and a changeup -- and a competitor's mentality.
"If I throw inside and a guy hits a home run off me, I'll throw inside again," Heesch said. "You've got to prove you can keep beating me before I give in to you."
Being a Cubs fan, Heesch knows all about the heartache his fellow fans have endured. This week was the organization's first Draft under the club's new regime of president of baseball operations Theo Epstein, general manager Jed Hoyer and senior vice president of scouting and player development Jason McLeod.
Many fans are excited for the future under that trio, including Heesch, who hopes to be a part of the turnaround.
"Oh my gosh. It's kind of unreal, to be a part of the first Draft class of the guy who broke the 'Curse of the Bambino,'" Heesch said. "To be a part of that is a huge deal. I understand what they're trying to do. Good pitching beats good hitting any day ...
"I'm excited for this Draft class, to see whether it's the future or if it isn't. I look forward to seeing all of us in action and, hopefully, on the same ballclub in a couple years winning a World Series."