Although his early career was less decorated as his brother’s, he showed consistent improvement and developed into a highly competitive rider.
He would sign with GEICO Honda to contest the 2014 and 2015 supercross seasons; for 2014, he raced the 450cc class, competing well with top 10s in 9 of the first 11 rounds, but missing the last 5 due to complications of dehydration leading to kidney problems.
Stewart sat out the 2016 Lucas Oil Pro Motocross Championship event in order to prepare for the 2017 racing season.
[5] Over time, he gained opportunities with factory-supported teams, including Smartop/MotoConcepts Honda and later Rockstar Energy Husqvarna Factory Racing.
In 2022, Malcolm joined the Rockstar Energy Husqvarna Factory Racing team for the full AMA Supercross 450cc season.