Sweeney was born in the West Park neighborhood of Cleveland, Ohio and graduated from that city's Saint Ignatius High School.

After Ohio switched to electing members of Congress by districts beginning in 1966, Sweeney decided to forgo a re-election bid and sought the Attorney General's office an additional time.

During his tenure as a county commissioner, he was a supporter of regional government, helped establish Cuyahoga's public defender's office and the solid-waste district.

During his research, he discovered an incriminating document that showed that the manufacturers of asbestos had been aware of its dangers for half a century but conspired to conceal the information from the public.

Sweeney died at the age of 82 on June 30, 2007, at his home in Gates Mills, Ohio, a Cleveland suburb, after suffering from a variety of ailments.