Biography of Jay Cooke Jay Cooke, an American financier, was born on Aug, in Sandusky, Ohio. He was the son of one of the first lawyers in the state of Ohio and a member of the Whig Party. Early Career and Financial Support for the Union On January 1, , just a few months before the Civil War began, Cooke opened his private banking firm, &;Jay Cooke & Company&;, in.