While Newt Gingrich may have joined Mitt Romney's campaign as a surrogate, the former House speaker and presidential candidate still isn't afraid to speak his mind about his recent opponent.

Gingrich on Thursday stood by some of his earlier criticisms of Romney from the Republican primary, including his argument that the former Massachusetts governor is a career politician.

"This is a guy who has thought about this, at least, since his father ran in 1968," Gingrich said in an interview on MSNBC, referring to the late George Romney, the former Michigan governor who ran for president in the 1960s but failed to capture the GOP nomination.

In a wide ranging interview with MSNBC's Chris Matthews, Gingrich defended his line of attack during the primary that the only reason Romney advanced in the private sector was because he lost his first big political campaign in 1994, when he ran for a Massachusetts Senate seat.

Gingrich agreed with Matthews' assessment that Romney's business career "was forced upon him by defeat."

"He wasn't a volunteer (citizen) after '94," Gingrich said, smiling.

Romney later went on to become a one-term governor of the state and ran for president in 2008.

Gingrich, however, did offer praise for the candidate he now stumps for on the campaign trail, although his enthusiasm could be characterized as mild at best.

"He is a good organizer. He is a very methodical person. He has prepared to systematically do what he thinks is right for the country," Gingrich said. "And I think he might turn out to make a surprisingly good president."

Gingrich took heat when he first offered an endorsement of Romney after ending his presidential run earlier this month. Critics argued his choice of words were less than enthusiastic. At the time he simply said Romney would make a better president than President Barack Obama.

"I thought, compared to me, I thought I was a better choice," Gingrich said Thursday. "Compared to Obama, I think Romney's a better choice."

Gingrich took the stage for the candidate at the Georgia GOP convention this weekend, and he's scheduled to appear with Romney at a Las Vegas event at the end of the month.