"I dare you, Class of 2013, to do better. I dare you to do better," Obama said.
In a sunbaked stadium filled with more than 57,000 students, friends and relatives, Obama lamented an American political system that gets consumed by "small things" and works for the benefit of society's elite. He called graduates to duty to "accomplish great things," like rebuilding a still-feeble economy and fighting poverty and climate change.
The visit to Ohio State - the first of three commencement addresses Obama will give this season - was a homecoming of sorts for Obama, who has visited the campus five times over little more than a year, starting with his first official campaign rally here last May.
He urged graduates to run for office, start a business or join a cause, contending that the health of their democracy "requires your dedicated, informed and engaged citizenship".
Ohio State bestowed an honorary doctorate on Obama, applauding his "unwavering belief in the ability to unite people around a politics of purpose".