Cooper's father, Kenny Cooper Sr., played professional soccer as a goalkeeper in England before moving to the United States to play for the Dallas Tornado of the North American Soccer League. Under the mentorship of his father, Cooper became an outstanding youth player.

After retiring from coaching professional soccer, Cooper's father had settled the family in Dallas, Texas where Cooper attended high school at Jesuit College Preparatory School of Dallas. He was the Dallas area high school player of the year while playing, graduating in 2003.

While playing with the Dallas Solar 85 Soccer Club in the Dallas Cup, a major international youth tournament, Cooper caught the attention of several former NASL players who contacted Jimmy Ryan, Director of Youth Football at Manchester United. Ryan had also once played with Cooper's father when they were both with the Tornado. Ryan contacted the Cooper's and invited him to England for a trial. The fact that Cooper's father was a native of England helped grease the skids for Cooper as United did not need to acquire a work permit for him.

Following a successful week long trial, United signed him on a free transfer. At the time Cooper had intended to attend Southern Methodist University, but decided to forgo college to pursue his professional career.