That's what friends and colleagues close to President Donald Trump's secretary of homeland security say about the retired general, who spent nearly five decades in the armed forces.

That means a few things: He's dedicated to his mission, he's loyal to his commander, and -- perhaps most important -- he's not used to being a political football.

Yet that's exactly where he's found himself as the face of the President's immigration policy, border wall and travel ban.

Friday he was in his comfort zone -- hosting a conference on security and economic prospects in Central America, a throwback to his time atop US Southern Command. The conference is also an example of how Kelly can be more comfortable with leaders from other countries than with leaders from his own, as Democratic members of Congress remain frustrated with the retired general.

Kelly had been retired for just eight months when he says he got a call in November from the Trump transition asking if he would serve again, this time in a civilian role that would be the centerpiece of Trump's aggressive border security and immigration agenda -- not mention securing the nation against terrorism.

Kelly said he turned to his wife after hanging up the phone to get her thoughts.

"True to form, my wife Karen said, 'Well if the Kelly family is nothing else, we're a family of service to the nation. And if they think they need you, then you've got to do it,'" Kelly said in an interview with CNN recently in his office.

Six months into the job, Kelly has already found that his military experience has given him unique advantages for the role -- but left him less prepared in other ways.

On the former, Kelly took a lead role in organizing the large conference that was held here Thursday and Friday, which convened top officials from the US, Mexico and Central America to discuss conditions south of the United States.

Kelly has talked about organizing the conference for months -- something he says he has wanted to do since he served as commander of Southern Command, the combatant command charged with security in Central and South America and the Caribbean.

In his early interview with then-President-elect Donald Trump, Kelly made clear that his approach to border security would start much farther south than the US-Mexico border, because his vantage point as the head of SouthCom for more than three years showed him that's where the flow of security threats -- including drug and human trafficking -- originate.

"Talking to President, then President-elect Trump, about the Southwest border, and my pitch to him (was) that the security of the Southwest border, if we're simply only fighting the fight to stabilize or to gain control of the border on the Rio Grande River, as an example, we've lost," Kelly said.

While Kelly "could be ignored adequately" in the last administration, this time around, "I was able to make it happen," he said.

Unused to politics

Although immigration and border security was a focus of Trump's campaign and has been a central focus of the Department of Homeland Security in this administration, Kelly's useful military experience goes beyond Southern Command.

Kelly served as a liaison to former Defense Secretary Leon Panetta, who recommended him for SouthCom, and he worked as a legislative assistant for the Marine Corps commandant in the mid 2000s.

But while Kelly said his long experience in the Pentagon helped him understand how Washington works in general, he says he was not prepared to become the political lightning rod that his new position has made him.

"What I never saw on the military side was the level of toxic kind of politics that are associated with what I do now," Kelly acknowledged, repeating what he frequently tells members of Congress who criticize his actions: If you don't like the laws, try to change them.

Panetta suspects Kelly is particularly uncomfortable when it comes to "schmoozing" politicians, a key part of the job of any Cabinet official.

"He's a guy who wants to do the job as best he can, and the last thing he wants to have to deal with is the political sniping that I'm sure is going on," said Panetta, also a CNN contributor. "It's probably not that comfortable for John, and it probably makes his job that much tougher because, again, this is a guy who has kind of a pretty straightforward approach to, 'This is my mission, and this is what I have to accomplish, and I haven't got time for the niceties of political chitchat.'"

Former Defense Secretary Robert Gates, whom Kelly also served as senior military assistant, noted that the retired general's legislative liaison experience gives him a lot of insight into how the government works, but military officials are simply not exposed to the politics of the place the way civilian officials are.

"I think that the political environment is more complicated and more challenging than it is in strictly a command role," Gates said.

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Kelly admits that he did not get off on the best foot with Congress. Democratic members of the House came out of one early meeting calling Kelly "dismissive" and expressing frustration. A subsequent meeting with the Congressional Hispanic Caucus in April went slightly better , though members emphasized that the bar had been set low going in.

Tension with Democrats

Caucus Chairwoman Michelle Lujan Grisham, a Democrat from New Mexico, said she gives credit to DHS for saying it wants to improve congressional relations after some early missteps, adding that Kelly's decorated military background and extensive experience with Central America are certainly positive for a Homeland Security secretary.

But she said Kelly's "temperament" is still a substantial concern, and said his admonition to lawmakers to "shut up" if they won't change the laws that his officers are "sworn to enforce" at a public event at George Washington University just two weeks after the Congressional Hispanic Caucus meeting was a step backward.

"I can't argue that the law isn't extremely strident or stringent," Grisham told CNN. "Ask any federal or immigration judge. Here's the difference: If you want to motivate Congress to do a better job -- and we could and we should -- don't tell them to 'shut up.' That's not a very professional way to do it."

He's also sparred on the Senate side with California Sen. Kamala Harris, who is the sole Democrat on the Senate homeland security committee who represents a state along the Southwest border. She was also one of only 11 Democrats to vote against Kelly's confirmation, mainly because he would not offer a commitment to protect so-called Dreamers, or those who came to the United States as children, under the Obama administration's Deferred Action for Childhood Arrivals (DACA) program.

Harris and Kelly have had multiple tense exchanges when he has appeared before her committee, and leaving a Democratic caucus meeting with Kelly earlier this spring, Harris could only offer the word "frustrated."

"Secretary Kelly's confirmation process raised concerns due to his failure to commit to protecting Dreamers, his inability to speak truth to power to this administration, and his lack of grasp of the implications of the policy perspectives he was supporting," Harris told CNN. "Nothing since then has changed."

To be sure, Democrats are staunchly opposed to Trump's immigration policies, the implementation of which fall to Kelly. For his part, Kelly has said his goal is to give lawmakers honest answers, though they may not like them.

But some have also become frustrated with Kelly over time after initially seeing him as potential moderating influence on Trump. In fact, many joined Senate Republicans in confirming him with 88 votes. Kelly has repeatedly taken credit for preserving DACA, including recently telling the Senate homeland committee that a future secretary "might have a different view" in imploring them to make it permanent. He also maintains that his agency has carried out the program, saying DACA recipient arrested either didn't have their DACA status current or voided it with a criminal infraction.

Democratic lawmakers do not agree, however, that the administration has been honest about whether all of those people had actually lost their status or whether due process was given.

Grisham said she agrees with the stated goal of the administration to target dangerous criminals for deportation, but says the numbers, which show a sharp increase in deportations of non-criminal undocumented immigrants, don't back that up.

"He says to us, 'I'm really not going to go after Dreamers, we're going to respect the law.'" she said. "If you respect the law, where's the due process for immigrant families? Where are the lawyers and judges for families? What are you doing about asylum and refugees? Those laws are on the books too."

Kelly acknowledges that when he took over, his department was designed to be less responsive to Congress and the press, something he realized over time he should work to correct.

"I think maybe most administrations try to do this -- there was an attempt to control absolutely the message," Kelly said, reflecting. "So in the defense, I would say, of both the Congress and early on in the press, we did not have a forward-leaning posture. ... I want to talk to the press and the Hill about what my people do, and frankly, shame on us if someone like you writes an inaccurate story."

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But Kelly's scolding tone for lawmakers returned as he criticized many for often calling his office with scant details on an incident they're supposedly investigating, or claim to have received no answers to letters they haven't yet sent, and then when he explains the truth of the matter, don't apologize.

"They never go to the press ... and say, 'You know what, I was dead wrong. Kelly just gave me an explanation. Thank goodness we have CBP people that are doing this job,'" Kelly said. "It's very frustrating. But that said, we have a sacred mission to protect the country and I'm proud of these people, and we'll protect them."

A loyal commander

Backing up his troops is another military trait that's in Kelly's DNA, Gates and Panetta said.

Gates took particular issue with the notion that Kelly is heartless, which is a caricature some on the left have been prone to paint.

"John has a very deep sense of duty, and if he's told, if he understands that that duty, as with his oath, holds him to uphold the law, he will uphold the law," Gates said. "The President has told him he wants stricter enforcement of the immigration laws and John will do that, but I think it's a mistake to think that he's heartless or he doesn't care about the consequences for those individuals."

Both Gates and Panetta, asked to share a story from their time with Kelly, brought up instances where Kelly grieved his son, Robert Michael Kelly, who was killed in combat in Afghanistan in 2010. On Gates' last trip to Afghanistan, Kelly visited his son's platoon in private. Panetta described witnessing Kelly visit his son's grave at Arlington National Cemetery.

"It was a very heavy blow to him and his family, and something I'll never forget is John Kelly talking, at Arlington, to his son's grave site," Panetta said. "And I just have to tell you, for all of the rough-and-tumble outside, there's an inside to him that is a combination of Irish and Italian, but it spells compassion."

To be sure -- as lawmakers have realized -- Kelly's protectiveness flares up when someone suggests that his new troops, the thousands of law enforcement officers that work for DHS, are not honorable. While he acknowledges bad apples must be penalized, he regularly emphasizes that his rank and file put their lives on the line to protect the nation every day.

"This (political) viciousness extended to the equivalent of the enlisted men and women of the US military, and frankly I can't stand for that, and I will always, always, always call them on it," Kelly said. "Criticize me, criticize the President, have at it. But for the men and women that are enforcing the laws that Congress passed, it's hard to get my arms around how that's justified."