But even as he shook hands with leaders in Brussels, Tillerson was dogged by rampant speculation back in Washington that his days in the Trump administration may be numbered.
Last week, CNN and other outlets reported
that President Donald Trump has grown frustrated with Tillerson and is considering replacing him with CIA Director Mike Pompeo.
Addressing State Department employees at the US embassy, Tillerson joked about some of the recent criticism over his management of the department, which has centered in part on persistent staffing gaps, and his focus on reorganizing the agency.
"It's been a real honor to serve," he insisted. "It's been a whirlwind because the day we stepped in. We had a lot of challenges on our plate."
"While we don't have any wins on the board yet," he acknowledged, "I can tell you we're much better positioned to advance America's interests around the world than we were 10 months ago, and it's all attributable to the great men and women of this department."
Tillerson's visit to the embassy was followed by a sitdown with the European Union's chief diplomat, Federica Mogherini, who took a somewhat stern tone in her remarks to reporters after the meeting, highlighting some of the areas of disagreement between the US and the EU.
In particular, Mogherini issued a warning to the Trump administration over reports the US may recognize Jerusalem as Israel's capital and announce plans to move the US embassy there in the coming days -- a move that is expected to draw criticism from key US allies and potentially jeopardize efforts to reach a peace deal between Israelis and Palestinians.
"We believe that any action that would undermine these efforts (to reach a peace deal) must absolutely be avoided," said Mogherini. "A way must be found through negotiations to resolve the status of Jerusalem as the future capital of both states so that the aspiration of both parties can be fulfilled."
Mogherini also emphasized Europe's commitment to the Iran nuclear deal, which Trump has disavowed in recent weeks.
The Trump administration is pushing its allies to take a stronger line against Iran over destabilizing activities outside the realm of the deal, but the effort has been met with resistance in Europe, where countries have stronger trade ties with Iran and see the deal as a success.
"These issues and activities of Iran cannot be ignored and cannot go unanswered," Tillerson emphasized in his own remarks Tuesday, "and we intend to continue to take action to ensure Iran understands this is not acceptable to us, and we look forward to working with European partners in that regard as well."
One area where Tillerson is hoping to gain more traction during his visit is in promoting greater burden sharing with NATO partners.
In a meeting later Tuesday with NATO Secretary General Jens Stoltenberg, Tillerson praised the leaders of many NATO member states, saying, "many have stepped up to confirm their commitment to the alliance, not just in words, but with treasure as well."
R.C. Hammond, a spokesman for Tillerson, told pool reporters traveling with the secretary that Tillerson and Stoltenberg discussed ways to ensure NATO countries are meeting their requirement to spent two percent of their Gross Domestic Product (GDP) on defense spending, as well as shared interests in the Middle East and Ukraine.
Hammond acknowledged that diplomats have been open in sharing their disagreements with the US on various issues, saying, "dialogues only work if they go two ways."
But he insisted that questions about Tillerson's standing within the Trump administration did not come up in these talks.
Tillerson will hold additional meetings in Belgium on Wednesday before heading on to Austria and France.