BY JAMES R. HAGERTY

GREENVILLE, Ohio—When Bill Good was a student at Auburn University in Alabama in the 1980s, he worked at a company producing American-made fitness equipment—a business eventually wiped out by low-cost imports from Asia.

He later worked at Char-Broil LLC, a Columbus, Ga.-based maker of grills, where he was involved in a decision in 2004 to move production to China from the U.S., an episode he recalls as "extremely painful." It was part of a vast tide of similar decisions that helped reduce U.S. manufacturing employment by about six million jobs, or one-third, between 1997 and 2010.

Last September, Mr. Good ...