Thursday, as he stood on the opposite end of the park inside the German chancellery, the mood was darker. The man replacing him is readying plans to build a physical wall on the US border. A wash of populist nationalism has dampened prospects of steady cooperation.
Bidding farewell in the same city he proclaimed his "hope and change" vision loudest, Obama instead warned of a dimmer change encroaching.
"There are going to be forces that argue for cynicism, for looking the other way with somebody else's problems, that are not going to champion people who are vulnerable because sometimes that's politically convenient," he said. "If we don't have a strong transatlantic alliance that's standing up for those things, we will be giving to our children a worse world. We will go backwards instead of forwards."
The forces he described spreading across nations — cynical, uncaring, politically craven shadows — mirror almost exactly his pre-election descriptions of Donald Trump, views he says haven't changed in the days since he met with the President-elect in the Oval Office.
As he departed Europe Friday underneath a persistent cold drizzle, Obama left behind few firm assurances that the continent's greatest fears aren't well-founded.
"The voice that helps to steer the world away from war, wherever possible, that's our voice more often than not," Obama said during his final remarks in Europe as President. "And we're not always successful but if that voice is absent or if that voice is divided, we will be living in a meaner, harsher, more troubled world."
On Friday, Obama met with his closest western allies and found a collection of counterparts in varying stages of political strife. France's Francois Hollande is suffering record-low approval ratings as he gears up for a re-election bid. Italy's Matteo Renzi has vowed to leave government if his proposed constitutional reforms fail next month. Britain's Theresa May has her attention squarely on how to remove her country from the European Union without prompting a financial disaster.
Even Angela Merkel, the German chancellor upon whom Obama piled praise, will face a challenge from the right if she decides to run for a fourth term. Obama left little doubt where he stood on her reelection prospects Thursday, saying he'd vote for her if he could.
Merkel, in her fashion, offered a tightly constrained view of the road ahead. She said she approached Trump's presidency with an "open mind," leaving the unknown details about the future of the relationship unsaid.
In a readout of his meeting, the White House said Obama and fellow leaders agreed to continue sanctions on Russia for its actions in Ukraine and urged them to continue intelligence sharing programs to counter extremism.
He also reaffirmed, yet again, his commitment to democratic values "at a moment of great change," urging the leaders "to continue seeking solutions to common challenges with the incoming US administration on the basis of the core values that define the United States and Europe as open democracies."
Obama planned his final stops in Europe as a valedictory return after a rancid political campaign, meant to cement his legacy here while assuring leaders and ordinary people the progressive message he proclaimed in 2008 was now being realized by a Democratic successor.
That was before Trump won in a surprise victory.
Now, the assurances Europeans want — promises of stability and an end to the unease gripping this continent — Obama is not prepared to deliver.
On core areas of cooperation, there's scant confidence about a way forward. Obama can't say, for example, that the Iran nuclear agreement will continue as written. He's not positioned to vow US commitment to the Paris climate accord going forward. Perhaps most worrying to his European allies, there's little he can say with certitude about Trump's plans for checking Russia's aggressions.
After an hour and a half with Trump last week, Obama was able to glean the President-elect's commitment to preserving NATO ties, a statement Obama repeated in nearly every set of public remarks he delivered in Greece and Germany.
But elsewhere, on deeper matters, there's little he can say with honesty about the road ahead.
He still feels Trump is unfit for office, he's suggested, though no longer says so out loud. He remains concerned about the rhetoric the candidate espoused on the trail, but is "cautiously optimistic" he'll tone things down once he's in the Oval Office. And he can no longer say with any confidence the nationalist wave that landed Trump in the White House won't take firmer hold here.
Even as Obama was standing at the Acropolis in Greece hailing the ancient wisdom of democracy, the French nationalist politician Marine Le Pen was declaring an end to the globalized vision he's worked to advance.
"Donald Trump has made possible what was presented as completely impossible," Le Pen told CNN in an interview Tuesday. "So it's a sign of hope for those who cannot bear wild globalization. They cannot bear the political life led by the elites."
Obama, too, has warned against the pitfalls of globalization. But his message has shifted from 2008, when he warned of those "left behind in a globalized world" during his speech in Berlin.
Back then, he was advocating for the world's forgotten corners — dissidents in Burma, children in Bangladesh, refugees in Chad. These days, it's the disenfranchised voters who tilted toward Trump who he says must be eased into an interconnected world.
"If people feel that they're losing control of their future, they will push back," he said.