Jeb Bush, former governor of Florida, center, speaks to the media following an event at a Pizza Ranch restaurant in Cedar Rapids, Iowa on Saturday. (Daniel Acker/Bloomberg)

Presumed Republican presidential candidate Jeb Bush is turning to a Wall Street veteran to serve in a top policy position -- and possibly to run his policy shop, once he formally launches a campaign.

The National Review reported late Wednesday that Bush is set to hire Justin Muzinich to serve as campaign policy director. Bush aides say he's only joining the team in a part-time role for now, but will eventually serve in some kind of senior policy position, possibly as policy chief.

The policy chief usually plays a major behind-the-scenes role, but it could be a more prominent position in a Bush campaign, given the wonky nature of the former governor, who expects aides to fully brief him on issues, eagerly absorbs as much information on policy as possible and often enjoyed sparring with reporters covering his two terms about the finer points of his policy proposals.

Muzinich didn't respond to requests for comment. The hire comes amid a flurry of new faces in Bush World, including Scott Jennings, a Kentucky-based operative and veteran of the George W. Bush administration, who is expected to serve as the campaign political director.

On Wednesday, aides also announced that Bush has hired two more staffers in New Hampshire: Rob Varsalone, who has worked for Sen. Kelly Ayotte (R-N.H.), and Nate Lamb, who served as field director for Republican Scott Brown’s failed Senate bid last year. They'll join Rich Killion, who will serve as Bush's state director.

Bush's apparent decision to hire Muzinich comes after he also hired April Ponnuru, a well-known conservative policy expert, to join his team. And Bill Simon, a former gubernatorial aide and current Walmart executive, has been helping to solicit policy ideas and potential hires.

Muzinich signals "an add, not a subtraction" to the policy team, according to one Bush aide familiar with the moves.

News of Muzinich's hire has earned early criticism or skepticism from conservatives and Democrats:

Here's Washington Post conservative blogger Jennifer Rubin, for example:

Democrats also joined in...

But Bush aides dismissed the chatter, saying Muzinich is qualified for the position and has known Bush for some time.

Muzinich currently serves as a vice chairman of Muzinich & Co., a New York investment firm. Previously, he was with the hedge fund EMS Capital and Morgan Stanley. He holds undergraduate and business degrees from Harvard University and a law degree from Yale University.

While he has a finance background, he's also presented several academic papers or newspaper op-eds. In Oct. 2007, he advocated giving tax credits to major corporations who invested overseas as a way to supplement or replace U.S. foreign aid:

"Congress should provide a 39-cent tax credit for every dollar of American investment in developing countries. If Company X were to build a $100 million factory in Madagascar, its tax bill would be reduced by $39 million. The lost tax revenue would be offset by reducing direct foreign aid by the same amount.

"The power of substituting tax credits for lump sums of cash is that while the cash would bring at most $39 million to Madagascar, the tax credit results in a $100 million investment. For the same cost to the federal government, Madagascar receives far more resources. And by leveraging its foreign aid dollars, the United States is better off too, for reasons from the creation of new markets to alleviating conditions that may aid terrorist recruitment."

He later expanded on the idea in a Hoover Institution paper published in the summer of 2008, calling it "A Better Approach To Foreign Aid:"

"Fixing foreign aid is vital to the U.S. national interest. Not only does aid play an essential humanitarian role, but it provides a number of direct benefits to Americans, from opening new markets to alleviating conditions that aid terrorist recruitment. The current system has proven over the past half century that it faces serious challenges. Tax credits for companies, and tax breaks for individuals offer a pragmatic, incremental solution that should appeal to both sides of the aisle."

He appeared in The Washington Post in Oct. 2013 in a piece co-authored by Glenn Hubbard, the dean of Columbia Business School and former chairman of the Council of Economic Advisers under George W. Bush. The pair proposed structural reforms at the U.S. Federal Reserve:

"The simplest way to encourage Fed governors to be vigilant for excesses is to make maintaining financial stability explicitly part of the Fed’s mandate. This would have two effects. First, governors would be required to search, proactively, for imbalances. In essence, Fed officials would have to approach the economy from a different perspective than would most Americans. They would need to look more suspiciously at situations of potential overheating, just as Supreme Court justices have to look more suspiciously than most Americans do at attempts to infringe on minority rights. Changing this frame of reference would increase the likelihood that Fed governors would address financial excesses for the simple reason that people are more likely to be counter-majoritarian when told it is their job to be so. A different job description is a much more dependable solution than relying on those in power to be extraordinary."