[2] O'Day played football for the Edinboro Fighting Scots from 1993 to 1996, helping the team finish with a 30-12 record during that period.

[4] O'Day was selected by the Toronto Argonauts in the second round of the 1997 CFL Supplemental Draft, and signed with the team on May 28.

In 1997, O'Day dressed for all 18 regular season games, starting 2 and backing up for 16, and the East Division Final against the Montreal Alouettes.

In 1998, O'Day once again dressed for all 18 regular season games, starting the first 2 and backing up for the final 16, as well as the team's East Division Semi-Final loss to Montreal.

In 2003, O'Day started all 18 regular season games at centre, and was named a CFL West Division All-Star for the first time.

[6] On April 30, 2007, it was announced that O'Day was the inaugural recipient of the Roughriders' President’s Ring, presented by Frontier Peterbilt and voted upon by the players for his leadership on and off the field.

Upon retirement, O'Day joined the Roughrider front office as Football Operations Coordinator for the 2011 season.

In February 2015, he signed a three-year contract extension to continue as Assistant General Manager, with Director of Football Operations added to his title.

[11] On August 31, 2015, O'Day took over as Interim Vice President of Football Operations and General Manager for the Roughriders after Brendan Taman was fired.

[14] In December 2015, O’Day was named Assistant Vice president of Football Operations & Administration under Jones,[15] holding these titles for the 2016, 2017, and 2018 seasons.

In January 2019, Jones resigned from his roles with the Roughriders in order to pursue an NFL coaching opportunity.

[16] On January 18, 2019, O'Day was named Roughrider Vice President of Football Operations and General Manager.

[15][17] In his first season in these roles, the Roughriders finished first place in the CFL West Division with 13 wins and 5 losses.