He played as a defensive end, quarterback, running back and wide receiver for the Ocean Lakes Dolphins football team.

He also played in the 2012 U.S. Army All-American Bowl, where he served as a team captain for the East squad.

[1] Also a standout track & field athlete, Harold was a state qualifier in the jumping events.

At the 2009 Beach District Outdoor Track Championship, he placed 3rd in the triple jump event with a leap of 13.40 meters (43-10).

[2] He earned a second-place finish in the shot put at the 2012 Tallwood Team Challenge, recording a career-best throw of 14.01 meters (45-8).

Harold announced on December 10, 2014, that he would forgo his senior season and enter the 2015 NFL draft.

[16] On August 23, 2018, Harold was traded from San Francisco to the Detroit Lions for a conditional 2020 draft pick.

[18] On August 9, 2019, Harold was traded to the Philadelphia Eagles for offensive lineman Ryan Bates.

[20] On December 10, 2020, it was announced that Harold had signed with the Toronto Argonauts of the Canadian Football League.