[4] After his time at Elon, Irwin joined Capital City of the Canadian Soccer League for the 2011 season and was named the team captain.
[12] Following his stint with Capital City, Irwin joined his hometown club, the Charlotte Eagles in the USL Professional Division.
In the final, held at BMO Field on December 10, Toronto were defeated by Seattle Sounders FC 5–4 on penalties, following a 0–0 draw after extra time; Irwin was able to stop Álvaro Fernández's spot kick during the shootout, but misses from teammates Michael Bradley and Justin Morrow ultimately proved to be decisive.
[19] On December 13, 2016, Irwin was selected by Atlanta United FC in the third round of the 2016 MLS Expansion Draft, but was immediately traded back to Toronto for Mark Bloom and allocation money.
[30] On December 6, 2022, Minnesota United FC announced it had signed Irwin to a two-year contract, beginning in 2023, in support of starting goalkeeper, Dayne St.