Obama also hailed US relations with Italy, saying America has many strong allies around the world but that few are as strong, reliable and capable as the boot-shaped country.
"In good times and in bad, we count on each other," Obama said.
Standing in the sun-washed Rose Garden after private talks on a range of world issues, Obama said during a news conference with Renzi that he counted his much younger counterpart -- Renzi is 41, Obama is 55 -- among his closest partners and friends on the world stage.
He said he'd like to see Renzi stick around.
"I think Matteo embodies a new generation of leadership, not just for Italy but also for Europe," Obama said.
The admiration was mutual. Renzi complimented the president on his leadership on economic issues and said he'd copied Obama by creating a "jobs act."
He said the initiative had created significant jobs in economically challenged Italy, calling it "at least a first step to leave our difficult situation."
He credited Obama's work on climate change and clean energy, and said the US had "shown us the way how to get out of fiscal crisis."
Hours earlier, Obama said it was a "bittersweet moment" as he and first lady Michelle Obama welcomed the Italian leader and his wife for an official visit and the final state dinner of Obama's presidency.
"We've saved the best for last," Obama said, grinning.
Obama kicked the White House apparatus into high gear to put the spotlight on a European leader he thinks highly of.
The sound of herald trumpets and a full dose of pomp and pageantry on the South Lawn were orchestrated to welcome Renzi, one of the few world leaders to receive such a reception from the White House.
After each leader spoke, they hugged briefly and patted each other on the back.
White House officials described the two leaders as ideologically sharing a great deal of common ground, most notably their belief in the importance of a strongly integrated Europe.
Britain's decision to exit the European Union is testing that vision. A December 4 referendum in Italy on the government's proposed overhaul of the constitution could derail Renzi's political future if it fails.
Renzi said the referendum is "about a fight against bureaucracy."
He called it "unbelievable" that Italy has changed governments more than 63 times in 70 years.
"If we win, Italy will be stronger in the debates in the EU," the prime minister said of the referendum.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)