Joe Biden and Benjamin Netanyahu have met in an effort to close the remaining "gaps" in the push for a Gaza ceasefire deal, the White House said.
The meeting at the White House came a day after Mr Netanyahu gave a fiery speech to Congress as thousands of pro-Palestinian protesters demonstrated outside.
US Vice-President Kamala Harris later met Mr Netanyahu and said she had voiced "serious concerns" over casualties in Gaza.
The prime minister faces pressure both at home and abroad to bring an end to the Israel-Gaza war, now in its ninth month.
He said he had known the US president for 40 years - and that Mr Biden 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 that Mr Biden had met, and that Yitzhak Rabin, a successor, was there as an assistant.
The meeting follows months of tension over the war in Gaza, with Mr Biden reaching the point in May, according to his friend and former defence secretary Chuck Hagel, where he said "enough is enough".
Mr Biden also previously publicly threatened to hold back weapons shipments if Israel launched a large-scale ground offensive in Rafah, prompting anger in Israel.
Mr Netanyahu said in June it was "inconceivable" for the Biden administration to withhold weapons and ammunition from Israel.
At a news briefing, national security spokesman John Kirby said the pair discussed the urgent need for a hostage release deal, the potential of conflict spilling over into Lebanon, the threat of Iran and the need to reach "compromises" in peace talks.
While Mr Kirby added that "gaps remain" in the US-Israel relationship, it was still "healthy".
"By healthy, I mean they're not going to agree on everything," Mr Kirby said, adding that Mr Biden was "very comfortable with the relationship he has with the prime minister".
Speaking to reporters after her own meeting with Mr Netanyahu, Vice-President Harris said the discussion was "frank and constructive".
Ms Harris is the likely Democratic presidential nominee now that Mr Biden has stepped down from his re-election campaign.
She said she has an "unwavering commitment" to Israel and its right to defend itself.
Ms Harris also expressed, however, "serious concerns" about Israeli operations in Gaza and the "dire humanitarian situation there".
"I will not be silent," she added. "It is time for this war to end."
"Let's get the deal done so we can get a ceasefire to end the war," she added. "Let's bring the hostages home, and let's bring much-needed relief to the Palestinian people."
The US and Israeli leaders also held a closed-door meeting with the families of seven US citizens still being held hostage by Hamas in Gaza.
Following the meeting, Jonathan Dekel-Chen - whose son Sagui was kidnapped from Kibbutz Nir Oz on 7 October - told reporters that the meeting was "productive and honest", although he did not provide details.
"We feel probably more optimistic than we have since the first round of releases in late November, early December," he said.
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, condemning protesters as "Iran's useful idiots".
The White House pushed back on Mr Netanyahu's characterisation of the protesters, with Mr Kirby saying that "it's not a phrase we would use" and "not a reflection of what we think" of the "mostly peaceful" protests.
Thousands of pro-Palestinian protesters took to the streets of Washington to accuse Mr Netanyahu of being a "war criminal".
Their loudspeakers and chanting could be clearly heard from the White House as Mr Netanyahu arrived on Thursday.
Police arrested 23 people on Wednesday, 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 left 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.
