Washington (CNN) Secretary of State Rex Tillerson celebrates one year in office on Thursday -- a modest achievement by some standards, but one his critics had dismissed as unreachable just months ago.

He has survived an epically rocky first year, during which he had to adjust to public sector life while serving under a mercurial boss who, at times, publicly undermined his diplomatic efforts on social media.

Tensions between President Donald Trump and Tillerson seemed to reach a boiling point in October, after NBC reported that Tillerson called his boss "a moron," leading some to speculate his tenure in Foggy Bottom would be short-lived.

But Tillerson, who says he's learning how to better communicate with the President, seems more determined than ever to keep his post, telling CNN in a recent interview he plans to be there at the end of the year.

"Hi, I'm the new guy"

Tillerson was sworn in on February 1, 2017, after a relatively contentious confirmation process during which he clashed with fellow Republicans who expressed reservations about his commitment to promoting human rights and his ties to Russian President Vladimir Putin.

He was seen as an outsider, even by Trump administration standards. He had never held public office and was not part of the Trump campaign.

Moreover, he was offered the post during his first ever meeting with Trump, reportedly because his silver coif and well-cut suits made him look the part . Of course, it didn't hurt that he came recommended by several Republican foreign policy heavyweights.

Addressing a skeptical State Department staff on his first full day in office, Tillerson paid tribute to the work of career professionals, and called for unity of purpose.

"Hi, I'm the new guy," he said, eliciting laughter and applause from the crowd, who seemed to respond warmly to his humility and self-professed CEO-mentality. "As such, I will depend on the expertise of this institution."

Early stumbles and growing frustration

Tillerson immediately made it clear he wouldn't be following in the footsteps of his recent predecessors, or upholding the diplomatic status quo.

One of his top priorities in taking the job was to overhaul the State Department's structure from top to bottom -- streamlining the organizational chart, updating the technological infrastructure, cutting the budget by as much as 30%, and questioning the value of various positions and offices.

The "redesign," as he called it, weighed down morale at the agency and drew criticism from members of congress.

Tillerson also began to be viewed within the State Department as a distant figure , insulated from career officials by a small cadre of trusted advisers.

In November, after a string of senior diplomats stepped down, the head of an organization representing the foreign servic e excoriated the State Department's leadership in a letter, saying the agency's senior tiers were "being depleted at a dizzying speed," resulting in "a decapitation of its leadership ranks."

Critics also began to worry about the dearth of senior professionals in key posts, due in large part to the slow pace of nominations at the White House.

He also ruffled feathers with members of the media, refusing to take journalists from the State Department press corps along on early foreign trips and avoiding interviews and press gaggles -- opportunities to clarify foreign policies to the American people.

Rumors of a "Rexit"

After NBC reported Tillerson's alleged "moron" quip in October, the State Department went into damage control mode. Tillerson faced cameras for an impromptu statement, but repeatedly declined opportunities to deny the comment.

"I'm not going to deal with petty stuff like that," Tillerson said from the State Department Treaty Room. "I'm just not going to be part of this effort to divide this administration."

His spokeswoman later denied the report on his behalf.

Tillerson insisted he shared a close relationship with the President, who he met with regularly at the White house.

But publicly, the President seemed to regularly undercut Tillerson's efforts. At one point -- before the NBC story -- Trump tweeted that Tillerson was "wasting his time" attempting new dialogue with North Korea. Trump also seemed to contradict Tillerson's statements on the dispute between Qatar and its Gulf neighbors, even as Tillerson was flying between Doha and Riyadh to try and broker a settlement.

Tillerson has also acknowledged the lack of a decisive foreign policy "win" during his first year in office

"Do we have any wins to put on the board? No," Tillerson told a town hall meeting of State Department employees Tuesday after recounting work to date on North Korea, Russia, Syria, China and a slew of other issues. "That's not the way this works. Diplomacy is not that simple."

In November, CNN and other outlets reported that the White House was considering replacing Tillerson with CIA Director Mike Pompeo, citing multiple government sources who cautioned that a final decision had not been made.

New momentum?

That shakeup, however, never came to fruition. Tillerson continued to conduct his signature "quiet diplomacy" from his seventh-floor office at the State Department, and on increasingly frequent foreign trips.

In a wide-ranging interview with CNN's Elise Labott in January, Tillerson insisted 2017 was a successful year for the State Department, and he plans to stay in office for the foreseeable future.

"I intend to be here for the whole year," he said, when pressed about his plans.

He said he was baffled by the persistent rumors of his impending exit, but insisted that Trump has never given him any indication his job is in jeopardy, emphasizing: "None whatsoever."

Tillerson acknowledged, however, that he and Trump have "different management styles," and that he's had to adjust the way he communicates with the President.

"I'm here to serve his presidency, so I've had to spend a lot of time understanding how to best communicate with him so I can serve his needs with information," said Tillerson, who was CEO of ExxonMobil before joining the administration.

"I do think one of my roles is to always give him all sides of the issues even when I know it's not the side that he really wants to consider," he added. "I think it's part of making good decisions that I know he at least has had visibility to all aspects of the decision he's about to make."

While Tillerson's second year in office was by no means inevitable, he can't afford to take a victory lap just yet.

His critics still openly worry about the effects his redesign will have on American leadership in the years to come, and his management decisions to date have generated controversy within the agency's Foggy Bottom headquarters.

Just last week, CNN reported that several career officials had retained attorneys over complaints they had been sidelined into menial jobs for political reasons.

But despite the controversy, the Texas oil executive is learning to adapt to the inside-the-Beltway world he so often claims to loathe.