Washington (CNN) Energy Secretary Rick Perry has been a near-ghost in Washington, adhering almost too well to the first rule of working for President Donald Trump — never overshadow the boss.

Perry generates so few headlines that it's easy to forget the longest-tenured Texas governor and two-time Presidential candidate is a Cabinet official.

Unlike several of his colleagues, Perry has avoided negative attention or scandal. He has also not run afoul of Trump on any major issue, and he's maintained good relationships on Capitol Hill. He's been a loyal soldier and a bit player in a show where Trump is the star.

He's part diplomat, part salesman, part presidential adviser. And 100 percent invisible. He's also readily deployable. Most recently, when Trump needed a high-ranking official to lead the US delegation to the inauguration of the new Ukrainian president , he turned to Perry.

Following the May 20 inauguration in Kiev, Perry conducted bilateral meetings with Ukraine's president, its prime minister, speaker of the Ukrainian parliament, and the president of Georgia. Perry briefed Trump Thursday morning at the White House.

While he isn't the most obvious commander-in-chief stand-in, the former Texas governor has emerged as a valued utility player in the Trump administration.

"I think the secretary is smart, but he's also savvy," Sen. John Kennedy, Republican from Louisiana, told CNN's Alex Marquardt. "He understands human relations, human nature and politics. He doesn't feel obligated to make news every day. "

Many who know him attribute Perry's relatively smooth tenure at Energy to his lengthy experience in public life. No other Trump Cabinet member has had a longer career in office.

First elected to the Texas state house in 1985, Perry served as the state's agriculture commissioner and lieutenant governor before serving an unprecedented 14 years as the governor of the Lone Star State.

"He's got 40-years of working in and around government," said Dave Carney, a Republican strategist who advised Perry both as governor and on his 2012 bid for president. "He knows you can't take shortcuts."

That means Perry has not been felled -- nor has he embarrassed the President -- by spending taxpayer dollars excessively on things like air travel or office furniture . And his considerable skills as a retail politician have helped him maintain cordial relations on Capitol Hill and within the department.

Perry's relative popularity among career staff have made him less susceptible to vindictive leaks. "He is a really good people person, and that translates to when he visits the labs and is saying hi to researchers and spending time with people," one senior energy official told CNN.

It also helps that the department he leads is relatively tiny in both budget and workforce -- smaller, in fact, than the entire Texas government. There's been little need or interest into aggressive oversight, and Perry has not had major standoffs with Capitol Hill over subpoenas.

It was not a given that Perry would even be in Trump's Cabinet. During his brief bid for the White House in 2015, Perry called the future president a "cancer on conservatism." By the time the general election rolled around, Perry was appearing on Dancing with the Stars

But Perry agreed to come out of retirement -- he had left the governorship in January 2015 -- to join Trump's Cabinet, just as Trump agreed to put aside Perry's criticism of him from the primary. In a twist of irony, Trump put him in charge of the very government agency that Perry famously forgot during his first run for the presidency.

At a Republican debate in 2011 , Perry said he would list three federal departments he would cut entirely. "Commerce, Education, and the, uh, what's the third one there" Perry said. He later clarified he meant Energy.

At last October's Atlantic Festival, Perry said that while the best job he'd ever had was being governor of Texas, being Energy secretary was the "coolest job I've ever had." Multiple people close to him say that Perry loves his job and shows no signs of leaving.

Bloomberg report in April, however, said that Perry "had been seriously considering his departure for weeks." Department spokeswoman Shaylyn Hynes said then that Perry is "happy where he is serving," a statement Hynes referred back to when asked about the report by CNN this week.

Sources close to Perry say he's more likely to stay in the administration through the 2020 election. "I would be surprised for him to leave in the near future," said a senior official at the department.

But Perry has also not ingrained himself into Washington life. He's rarely seen out to dinner, and never at the regular hangout for Trump administration officials, the Trump Hotel. He prefers, say those who know him, to take walks through Arlington Cemetery in the evenings.