Grayson attended Heritage High School in Vancouver, Washington, where he was a three-sport standout in football, basketball, and track.

He guided the Timberwolves to three straight Class 4A playoff berths and a GSHL championship in 2008.

He broke most of Washington's Class 4A state passing records, and had the nation's highest completion percentage as a senior (73.2 percent), topping over 10,000 yards in total offense during his career.

Also a standout track & field athlete, Grayson lettered all four years competing in sprinting, hurdling, jumping and relays events.

[6] As a true freshman at Colorado State University in 2011, Grayson started three of four games he played in.

Grayson entered his sophomore season in 2012 as the starter until he was injured in the team's fifth game against Air Force.

[22] Grayson signed with the Salt Lake Stallions of the Alliance of American Football (AAF).

[26] On August 8, 2019, it was reported that Grayson confirmed he was "stepping away" from football after declining an offer from the Falcons.