Greenwood was born and raised in Kingston, Ontario, where he attended Regiopolis-Notre Dame Catholic Secondary School.

In his senior year, he was the recipient of the Presidents' Trophy for best defensive player in Canadian Interuniversity Sport football.

Greenwood had a bit of a breakout season in 2016, despite missing a number of games due to a knee injury he suffered in August.

[12] He tore his anterior cruciate ligament on the first day of training camp and missed the entire 2017 CFL season.

In the playoffs, which culminated in the Stampeders winning the 106th Grey Cup, Greenwood had three more special teams tackles.

[15] Greenwood's 2019 season saw him play in 12 games, making a then-league leading 79 tackles, as well as two sacks, an interception, and three forced fumbles.

However, like in previous seasons, Greenwood was unable to stay healthy and ended up of the injured list following week 14.

[16] He returned to play in the Stampeders' West-Semi Final loss to the Winnipeg Blue Bombers, where he recorded three defensive tackles.