[13] He officially signed with the club on March 1, 2019[14] and made his professional debut appearance the following day, starting in Orlando's season opener, a 2–2 draw with New York City FC.

[15] As part of Orlando's end-of-season roster decisions it was announced Miller had his contract option for the 2020 season exercised.

[23] In October 2023, Miami announced that they had signed Miller to a contract extension through the 2026 season, with a club option for 2027.

[24] Ahead of the 2024 season, he was traded to the Portland Timbers for $625,000 in general allocation money, an international roster spot, plus another $150,000 GAM in performance-based incentives.

Miller was named to the Canadian U-23 provisional roster for the 2020 CONCACAF Men's Olympic Qualifying Championship on February 26, 2020.

[26] On March 18, 2019, he received his first senior call-up for Canada for their final CONCACAF Nations League qualifying game against French Guiana.