Mr Blinken pointed to Benjamin Franklin's journey to France during the Revolutionary War to drum up support for the American military — a visit that left a lasting impression on the founding father.
“For more than two centuries, the United States and France have built upon the foundation of those early ties — and today, we are unwavering security allies, close economic partners and most of all, cherished friends,” Mr Blinken said.
Now, in the post-Cold War era, Mr Blinken said the world faces a new set of challenges, including the war in Ukraine, ensuring the advancement of an open Indo-Pacific region and staving off future pandemics.
“This is a challenge that we can best meet as friends, and, for the United States, alongside our very first friend,” he said.
“The bottom line is this: it’s hard to find a challenge that we can’t solve if the United States and France work together.”
Mr Macron added: “We are very much engaged together to help the Ukrainians in this war and to resist to the Russian aggression.
“And I want to thank your country for the unique commitment and investment alongside the Ukrainian people and in great solidarity with the Europeans.”
Ms Harris said the US and France will be “guided by our shared history and our shared vision for the future”.
In a separate meeting earlier this week, Ms Harris and Mr Macron discussed space exploration efforts, as the French President lobbied to place one of his compatriots on the spacecraft that will send a new batch of astronauts to the Moon in 2025.
“I have a candidate for flying … to the Moon,” he told Ms Harris at Nasa headquarters on Wednesday. “He wants to go to Artemis 3.”
The President was referring to French astronaut Thomas Pesquet, who has gone to the International Space Station twice.
Mr Macron's visit to the US is the first state visit during President Joe Biden's administration.
At an elaborate dinner hosted at the White House on Thursday night, both leaders expressed their nations' continued commitment to Ukraine's defence.
The French leader is expected to speak with Russian President Vladimir Putin in the coming days. Mr Biden said he would meet Mr Putin only if Russia leaves Ukraine, an offer that was rejected by the Kremlin.