The former head of the Defense Intelligence Agency has recently landed on the list of most talked about vice presidential possibilities. The presumptive GOP nominee is expected to make a decision this week before the Republican National Convention begins in Cleveland on Monday.
Trump has said that he wants a D.C. political insider, but he may instead look to boost his national security credentials with Flynn. And even if Flynn doesn't get the nod, he is likely to hold a key Trump administration post -- with his increasingly prominent role in the campaign signaling new directions that Trump's foreign policy may take.
While Flynn shares many of the same criticisms over the fight against radical Islam and U.S. intervention in Libya that Trump has lobbed at the Obama administration, he appears to favor a more internationalist approach to combating terrorism and engaging with other countries.
The decorated military figure told ABC's "This Week" on Sunday that he didn't know if he was being vetted for VP, but he said he was "honored to be even in this discussion."
Flynn would be the first general to appear on the ticket of a major party in over 50 years. Ross Perot, another billionaire businessman who ran as an outsider candidate, picked decorated veteran Vice Adm. James Stockdale as his VP.
Flynn is also a self-professed Democrat, making a Trump-Flynn ticket the first since 1864 to have a Republican and Democrat running together.
Party affiliation isn't the only place where Trump and his possible running mate diverge.
Flynn told Al Jazeera English in May about Trump that he "doesn't agree with everything he's said," refusing to fully endorse the candidate's calls to bring back waterboarding and for "taking out" terrorists' families.
"There must be more precision in the use of the language that he uses as the potential leader of the free world," Flynn said then, adding that is the "advice that I'm trying to get into him."
Perhaps most significantly, Flynn has advocated for longer-term U.S.-led multinational interventions, including elements of nation-building, in the Middle East. Trump has repeatedly slammed that concept.
While Trump used his April foreign policy speech to rail against nation-building in the Middle East, Flynn has said the "military solution is not the end-all," advocating a nation-building effort akin to the 1990s international peacekeeping missions in the Balkans.
"We started there in the early 1990s to create some stability and we are still there today," Flynn said.
Flynn's belief that stability in the region requires a long-term effort was held while he was still in uniform. He told CNN's Evan Perez that the problems in the region defied quick-fix solutions, saying, "We've got to be very careful that we're not looking for the headline."
"We have to start thinking about what is this place going to be like, you know, 10 years from now, 20 years from now," he added.
Trump had promised in April that ISIS would be vanquished "very, very quickly."
However, the two men also agree on key national security issues, ranging from criticism of the Iran nuclear deal to Hillary Clinton's use of personal email while secretary of state.
Despite serving as the Pentagon's top intelligence officer, Flynn has slammed the Obama administration for its handling of the fight against ISIS and echoed Trump in denouncing Obama's terminology for the terrorist group.
"It infuriates me when our president bans criticism of our enemies, and I am certain that we cannot win this war unless we are free to call our enemies by their proper names: radical jihadis, failed tyrants, and so forth," he wrote in an op-ed in the New York Post
He also blasted U.S. leaders for failing to design a strategy and argued they "timidly nibble around the edges of the battlefields from Africa to the Middle East."
Flynn's more than 30-year-long Army record included leading military intelligence efforts in Afghanistan and Iraq and helping to oversee Special Operations Forces.
He acknowledged in the Post that he was "let go" as director of the Defense Intelligence Agency for holding views that clashed with other administration officials regarding the direction of the agency.
Flynn also shares Trump's vocal opposition to the Iraq and Libyan interventions in 2003 and 2011, telling Der Spiegel that removing Saddam Hussein and Moammar Gadhafi helped spread instability and violence.
On the decision to invade Iraq, Flynn said, "History will not be and should not be kind with that decision."
The retired lieutenant general's increasingly prominent role in the Trump campaign, despite differences in their foreign policy worldviews, is raising the prospect that Trump might defer to established military leaders like Flynn should he win in November.
Another of Trump's military advisors, retired Rear Adm. Charles Kubic, acknowledged that Trump's rhetoric may differ from actual national security policies, telling CNN's Kyra Phillips in April: "I think he is prone to drawing (a) very stark contrast when he's trying to make a point."
Flynn seemed to echo this sentiment while appearing on Al Jazeera English in May.
"Read his book, 'The Art of the Deal.' Start really, really high and really. Really hard," Flynn related. "And then be prepared to get down to where you think you can actually negotiate."