The Daniel High School junior made the call shortly after 2012 defensive end Shaquille Lawson inked with Clemson.
"I really didn't have to think about it," Greenlee told CUTigers on Wednesday. "Me, Shaq and coach Rob [Randy Robinson] all talked about it. Shaq was like, ‘It would be a nice thing to do.'"
At the end of Lawson's signing ceremony, Daniel athletic director Tommy Plumblee told the crowd there was one more announcement.
With his pledge, Daniel's proud tradition of sending football players across town to Clemson will continue for at least another year. The current streak started in 2010 with Greenlee's cousin, DeAndre Hopkins. It continued a year later with DeShawn Williams and rolled on for another with Lawson.
"[Hopkins] is basically my big brother. He's my God brother. That's my first-cousin," Greenlee said.
He will make it No. 4 in a row from Daniel to Clemson. And that's what he's always wanted.
"That was one of my lifetime dreams that I just accomplished," he said.
The 6-3, 205 pound prospect committed to Clemson over interest from Maryland, Tennessee, N.C. State and Wake Forest.
As a junior, he had 91 tackles, two interceptions and four fumble recoveries.
Greenlee joins offensive tackle R.J. Prince in the Tigers' 2013 class.