Benjamin Netanyahu has paid tribute to “50 years of support for the state of Israel” from Joe Biden as the pair met at the White House.
The meeting came a day after the Israeli prime minister gave a fiery speech to Congress as thousands of pro-Palestinian protesters demonstrated outside.
The Israeli leader faces pressure both at home and abroad to bring an end to the Israel-Gaza war, now in its ninth month.
Mr Netanyahu said he had known Mr Biden for 40 years – and that the president had known every Israeli PM over the last half a century.
“From a proud Jewish Zionist to a proud Irish-American Zionist, I want to thank you for 50 years of public service and 50 years of support for the state of Israel,” he said.
Mr Netanyahu also said he looked forward to working with Mr Biden “on the great issues before us” over the next several months.
The US president joked that Golda Meir was the first Israeli PM he had met, and that Yitzhak Rabin, a successor, was there as an assistant.
The pair were expected to discuss Gaza, a ceasefire with Hamas and a possible hostage release during the meeting.
Mr Netanyahu also plans to meet Vice-President Kamala Harris, the presumptive Democratic nominee after Mr Biden announced he was stepping down.
Speaking in the House chamber on Wednesday, Mr Netanyahu defended Israel’s war in Gaza, while attempting to rally support from US politicians.
“Our enemies are your enemies,” he said, and condemned protesters as “Iran’s useful idiots”.
Thousands of pro-Palestinian protesters took to the streets of Washington to accuse Mr Netanyahu of being a “war criminal”.
Police arrested 23 people, including five inside the Capitol building.
Mr Netanyahu’s speech was occasionally met with rapturous applause, mostly led by Republicans.
The Gaza war has deepened political divides in Washington, and led to infighting among Democrats whose progressive wing has been critical of US support of Israel.
Congresswoman Rashida Tlaib was spotted sitting in the audience holding a sign that read “guilty of genocide”.
Ms Harris did not attend Mr Netanyahu’s speech due to scheduling conflicts, the White House said.
Instead, she spent part of the day speaking to a crowd from the historically black sorority Zeta Phi Beta.
Ms Harris has expressed steadfast support for Israel. However, such a stance has been politically costly for the Democrats.
Hundreds of thousands of protest votes were cast against Mr Biden during the presidential primaries by those wanting him to stop sending military aid to Israel.
Some of those angered by his war stance see Ms Harris as a chance to mend the fracture in the party, and win back the votes.
Mr Netanyahu is expected to visit Republican presidential nominee Donald Trump at his Mar-a-Lago residence in Florida on Friday.
