As a coach, Smith won the Memorial Cup in 2015 and spent four years as an assistant with the Maple Leafs before joining Ottawa.
Smith appeared in 61 games with the Spitfires during his rookie season in 1994–95, scoring four goals and 17 points, while accumulating 201 penalty minutes, the second most on the club.
In the post-season, Smith scored a goal and eight points in five games, as Windsor lost to the Sarnia Sting in the first round of the OHL playoffs.
On March 26, 1997, Smith played in his first NHL game, earning an assist on a goal scored by Brandon Convery, as the Maple Leafs defeated the San Jose Sharks 2–1.
In four post-season games, Smith had no points, as the Maple Leafs lost to the Saint John Flames in the Atlantic Division semi-finals.
[citation needed] In 1998–99, Smith saw his offensive production increase in St. John's, as he scored seven goals and 35 points in 79 games, as he was the highest-scoring defenceman on the team.
[citation needed] Smith returned to St. John's for the 1999–2000 season, as in 74 games, he scored six goals and 28 points while ranking second on the team with 197 penalty minutes.
[citation needed] Smith joined the Hershey Bears, the American Hockey League affiliate of the Colorado Avalanche, for the rest of the 2001–02, following his trade by the Toronto Maple Leafs.
On October 17, 2002, Smith played in his first game with the Avalanche, as he had no points, and a fight with Ian Laperrière, in a 4–1 win over the Los Angeles Kings.
[citation needed] In 2006–07, the Spitfires replaced Mantha with Bob Boughner as the new head coach, as Smith remained with the club as an assistant.
The rebuilding Spitfires struggled to a record of 18–43–7, earning 43 points and ninth place in the Western Conference, as the club failed to reach the post-season.
At the tournament, Windsor put up a perfect record of 4–0, including a 9–1 win over the Brandon Wheat Kings in the final game, to clinch their second consecutive Memorial Cup championship.
[citation needed] Bob Boughner returned to the Spitfires in 2011–12 as head coach, as Smith remained with the club as an assistant.
Windsor began to rebuild during this season, as the club struggled to a 29–32–7 record, earning 65 points, and eighth place in the Western Conference.
[citation needed] Following the 2011–12 season, Smith resigned from his position with the Spitfires, as he was hired to become the head coach of the Oshawa Generals.
[citation needed] Smith joined the Oshawa Generals of the Ontario Hockey League as head coach for the 2012–13 season.
On September 20, 2012, Smith coached his first career OHL game, earning the victory as the Generals defeated the Peterborough Petes 5–2.
At the tournament, the Generals finished with a perfect record and defeated the Kelowna Rockets 2–1 in overtime in the final game to win the Memorial Cup.
[citation needed] The rebuilding Leafs saw improvement during the 2016–17 season, as Toronto finished with a 40–27–15 record, earning 95 points, and the second wild-card seed in the Eastern Conference.
[citation needed] Toronto continued to improve during Smith's third season with the team in 2017–18, as the Maple Leafs had a 49–26–7 record, earning 105 points, and third place in the Atlantic Division.
[citation needed] On May 23, 2019, the Ottawa Senators announced that Smith agreed to a three-year contract to be the team's head coach.