Missouri native Alec McDonnell played in Major League Rugby between 2020-2025. He represented the Rugby New York Ironworkers (2020), the Houston SaberCats (2021-2023), and the Miami Sharks (2024-2025).

McDonnell is a Lindenwood University alum, attending from 2015-2019. He signed with Rugby United New York training squad ahead of the 2020 season, and made his MLR debut from the bench before the season was cancelled after only 5 rounds due to the COVID-19 pandemic. He moved to Houston in the fall and played for Rugby HTX, the SaberCats academy side (now SaberCats 2) between 2020-2022. He made the senior SaberCats side in 2022, earning 9 caps (8 starts) during that year’s MLR season, and appeared in a career high of 16 appearances during the 2023 season for the ‘Cats, primarily in a substitute role. Through the 2023 season, McDonnell has earned 26 MLR caps (10 starts) between New York & Houston.

On 16th December 2023, the Miami Sharks announced the signing of Alec McDonnell for the 2024 season, where he earned 4 starts and appeared in all 16 games during the Sharks’ inaugural season, where they recorded solid and competitive results despite missing the post-season. On November 26, 2024, the Miami Sharks announced the return of Alec McDonnell for their 2025 season. McDonnell earned a career high 10 starts for the Sharks in 2025, appearing in 15 games to pass 50 Major League Rugby appearances in his career. He also tied his career high of 55 tackles made, recording over 50 tackles made for the 4th straight season.

Following the withdrawal of the Miami Sharks from Major League Rugby during the 2025/26 offseason, Alec McDonnell announced his retirement from professional rugby on Instagram on 25th February, 2026 after 6 seasons and 57 appearances in the competition.