Lennon returned to Real Salt Lake in early 2017, ahead of agreeing a season-long loan with the club.

Initially expected to play a developmental role, injuries to key starters thrust Lennon into the starting lineup as the season progressed.

[6] He made his competitive debut for the club in early 2020, appearing in Atlanta's 3–0 victory over Motagua in the opening stages of the CONCACAF Champions Cup.

[7] Lennon quickly established himself as a starter,[8] growing into a more advanced leadership role by the time he reached his third season with the club in 2022.

[11] On January 8, 2018, Lennon received a call-up for the United States men's national soccer team for a friendly against Bosnia and Herzegovina.