Welch, executive chairman of Jack Welch Management Institute, said Trump is on the right track with policies that would boost the economy but with "crappy management practices."
Calling Trump's firing of James Comey as FBI director last week a "rookie mistake," Welch said, "You don't make any friends doing it the way [Trump] did it."
While giving Trump a D minus for management, Welch said he gives the president an A on policies such as tax reform and deregulation and on his Cabinet and Supreme Court picks.
"I [also] give him an A on the morale of the business community and the morale in the country — the spirit in the country — the consumer confidence [and] the new salaries for kids getting out [of college]. There's an air of confidence," he said.