[9] Osorio made his debut for Toronto FC in Major League Soccer on March 9, 2013, against Sporting Kansas City, coming on for Terry Dunfield.

[14] In the 2017 season, Osorio saw a decrease in playing time; largely appearing off the bench as a result of the signing of Víctor Vázquez.

[19] In the first leg of the 2018 Canadian Championship final, held on August 8, Osorio scored in a 2–2 away draw against Vancouver Whitecaps FC.

Osorio was awarded the George Gross Memorial Trophy as the most valuable player of the tournament, having scored three goals in four games in the competition.

[21] He signed a multi-year contract extension with Toronto on August 30, 2018,[22] which made him one of the highest paid Canadian players in the world.

[25] On April 24, 2022, in a regular-season match against New York City FC, Osorio reached 300 appearances for Toronto, becoming the first player ever to do so for the club.

[26] At the conclusion of the season, Osorio's contract with Toronto FC expired, with the player confirming that "Everything's an option at this point" in regards to his next move.

[28] In March 2023, it was revealed his contract made him a Designated Player under Major League Soccer's salary cap rules.

[31] Osorio made his senior international debut on May 28, 2013, coming on as a second-half substitute for Samuel Piette in a 1–0 defeat to Costa Rica at Commonwealth Stadium.

[39] On October 7, 2021, during a 2022 FIFA World Cup qualification match, Osorio scored a goal against Mexico in an eventual 1–1 draw.