He had also struggled to match the considerable campaign funds raised by his Democratic rivals.
During his presidential campaign, Kucinich had called for an immediate withdrawal of US troops from Iraq, was in favour of gay marriage and universal healthcare and had called for the formation of a "department of peace" in the US government.
Last year he hit the headlines for attempting to impeach Dick Cheney, the US vice president, over his involvement in the Iraq conflict.
His run was a second attempt to run for the presidency, however his campaign had become an issue in his home state, where opponents said he was neglecting his constituency.