Bethlehem Steel McKenzie's performance in the academy ranks earned him call-ups to the
Bethlehem Steel FC roster, the Union's
USL team. He made his professional debut against
New York Red Bulls II in June 2016. Over two seasons, McKenzie made eight appearances for the Steel as an amateur player. He made 20 appearances his rookie season with the Union, mostly starting alongside fellow homegrown centerback,
Auston Trusty. McKenzie's appearances and performance on the backline earned him a nomination for the 2018
MLS Rookie of the Year Award. After losing his starting spot in the first team during the first half of the
2019 season, he reentered the line-up establishing himself as an initiator of attacks as a left-sided centerback. He retained his starting role through the
2020 season, earning accolades along the way. By mid-season, he made the Best XI for the
MLS is Back Tournament. McKenzie's first professional goal for the Union was a long-range equalizer against
D.C. United in October 2020. McKenzie finished the season with two goals and three assists from 22 matches, contributing to the Union's first trophy in the
2020 Supporters' Shield. His performances named him to the
MLS Best XI and nominated for the 2020 Defender of the Year (finishing second in the voting).
Genk On January 7, 2021, McKenzie joined
Belgian First Division A side
Genk, signing a four-and-a-half-year deal. McKenzie made his debut for Genk on January 24, starting in a 2–3 loss against
Club Brugge. He finished his first season making 16 appearances in all competitions and helped Genk win the
Belgian Cup.
Toulouse On August 16, 2024, McKenzie signed with
Toulouse in France. ==International career==