But if front-runner Donald Trump were the GOP nominee, Welch said he'd support the billionaire real estate mogul as his party's choice to prevent the Democrats from keeping the White House.
Welch told CNBC about 18 months ago that he'd like to see Cruz run. On "Squawk Box" on Wednesday, Welch said the Texas conservative is "the straightest guy you'll ever meet in terms of telling like it is."
"The craziest thing that ever comes out of Donald Trump's mouth is 'lying Ted,'" Welch said, referring to Trump's refrains in debates and on the campaign trial.
"Ted Cruz is the one guy … [who] does what he says," Welch said a day after Trump won Tuesday's delegate-rich Michigan and Mississippi primaries and the Hawaii caucuses. Cruz won Tuesday's other contest in Idaho.
Earlier this month, Welch tweeted:
Welch, who was CEO of General Electric for 21 years and is now executive chairman Jack Welch Management Institute, said Wednesday he's "not anti-Trump," but feels Cruz has better ideas for the transforming country.
"On jobs, I don't think there's anybody close to [Cruz]," he continued. "[Cruz's] tax plan is a real job creator."
Born to a working class family in Salem and with strong ties to Massachusetts, Welch was critical of the anti-Trump speech delivered last week by Mitt Romney, the former governor of the state and the 2012 GOP nominee. "It would have been better left in the drawer."
"I'm a Mitt Romney fan," Welch said. "[But] I didn't like that speech. That's one thing in a long resume of performance."
Welch said he's 100 percent with Cruz. But if he had to bet on who's going to get the GOP nomination, Welch said the odds in Trump's favor by 7 to 3.
"I want Cruz. But I acknowledge he's got a harder path right now. And last night was a big night for Trump," Welch said.
Despite opposition, former Romney adviser Vin Weber told CNBC's "Squawk on the Street" it's almost impossible to imagine another candidate entering the Republican convention with more delegates than Trump.
"So the question is, 'Can he be slowed down just enough so that you go into the convention and have an open convention?' And then who knows what happens," said Weber, now a partner with global public strategy firm Mercury.
Ahead of next week's winner-take-all primaries in crucial states of Ohio and Florida, Rubio failed to crack double-digit support in Michigan, while Kasich ran a close third to Cruz in Michigan, a state he had expected to perform better in.
While Kasich and Rubio still hope to win their home states, Trump tops the latest local polls.
Trump leads Rubio in Florida by nearly 15 percentage points, and is ahead of Kasich in Ohio, but by less than 5 percentage points, according to the RealClear Politics polling aggregator.