In Ohio, you must be at least 18 years old and possess a valid Ohio driver's license for intrastate (within the state of Ohio) commercial driving. Drivers must provide proof of residency in Ohio and also either U.S. citizenship or permanent residency. To drive interstate (state-to-state) or transport hazardous materials, you must be at least 21.
It's important to note that some employers may have higher age requirements and other conditions depending upon the position.