Greenwood attended Martin Luther King High School, where he was teammates with future NFL player Nick Perry.
[2] He suffered a torn lower abdomen muscle during OTAs in May, and was forced to begin training camp on the physically unable to perform list.
On September 25, 2013, the Dallas Cowboys signed Greenwood off the Lions' practice squad to provide depth while Morris Claiborne recovered from a shoulder injury.
[6] In 2014, Greenwood did not adjust well enough to Teryl Austin's new defensive philosophy and missed a significant part of training camp with a strained hamstring.
Greenwood is the nephew of former NBA players, Barry Wayne Stevens & Jeff Grayer Sr.