Grant Stoneman's soccer career has been marked by steady progression and notable achievements. He began his journey in college soccer, first playing at Wisconsin before transferring to Loyola University in Chicago. At Loyola, Stoneman distinguished himself, earning accolades such as Second Team United Soccer Coaches All-America and First Team United Soccer Coaches All-West Region in 2016 and 2018, as well as being named the Missouri Valley Conference Defensive Player of the Year in 2018. He also made the First Team All-Missouri Valley Conference in 2016, 2017, and 2018, concluding his collegiate career as the MVC Defensive Player of the Year.

Post-college, Stoneman started his professional career with Lansing United of the National Premier Soccer League in 2016. He then moved to the USL League Two, playing for Chicago FC United from 2017 to 2018, appearing in 18 games. His career progressed to the USL League One with Lansing Ignite, where he played in 23 games. Stoneman's significant breakthrough came when he joined SD Loyal, making his USL Championship debut and starting as a defender in the team's inaugural match against Las Vegas Lights. He quickly established himself as a key player, earning a starting position on the right side of Landon Donovan’s defensive line.

In November 2023, Stoneman joined Rhode Island FC as a key roster addition in preparation of their inaugural season in 2024 USL Championship.