According to the 2020 United States Census, Kennesaw has a population of roughly 33,000 residents within its city limits, though the broader Kennesaw postal area and sphere of influence encompasses many more people.
The city has seen steady growth over the last three decades, largely driven by the expansion of the Atlanta metro area and Kennesaw State University. The presence of the university gives Kennesaw a notably younger median age compared to surrounding suburbs, with a large population of young adults and college students. The community is increasingly diverse, with significant and growing African American, Hispanic, and Asian populations alongside a white majority. Education levels in the city are high, correlating with a strong median household income and robust employment rates.