Marcinkowski played for the Georgetown Hoyas for three seasons, from 2015 to 2017, where he achieved a 0.84 goals against average (GAA) over 56 appearances. In his final season at Georgetown, he captained the team to a 2017 Big East Conference Men's Soccer Tournament championship win, his second with the team.[2] He also played two games for the USL PDL side Burlingame Dragons.[3]
Professional
Marcinkowski signed a Homegrown Player contract with the MLS side San Jose Earthquakes on December 6, 2017, after spending four years prior to his college career with the team's academy. He was San Jose's third ever Homegrown signing to the first team, after Tommy Thompson and Nick Lima.[4] Marcinkowski was then temporarily loaned to San Jose's USL affiliate Reno 1868 FC, and played his first game for the team in Reno's 3–4 loss to Swope Park Rangers on March 17, 2018.[5]
On January 16, 2025, Marcinkowski signed a two-year deal with LA Galaxy as a free agent.[6]