[1] Stewart was a regional field director for the Louisiana Democratic Party during Senator Mary Landrieu's 2002 run-off campaign.
He had the same job as a regional field director for the South Dakota Democratic Party during Senator Tim Johnson's 2002 re-election campaign.
For the Obama for America campaign, Stewart was the director of field operations in the Iowa caucuses,[3] where the candidate's first place win established him as a serious challenger to then front-runner Hillary Clinton.
In this role, he helped build what The Guardian called "a historic ground operation that will provide the model for political campaigns in America and around the world for years to come.
[10] In August 2024, Stewart was named senior advisor for battleground states for Kamala Harris's presidential campaign.