The high-stakes meeting between Biden and Putin comes on the heels of a summit with NATO leaders in Belgium's capital, another first for Biden as U.S. president.

"What I'll convey to President Putin is that I'm not looking for conflict with Russia but that we will respond if Russia continues its harmful activities," Biden said at a press conference in Brussels. "And we will not fail to defend the trans-Atlantic alliance or stand up for democratic values."

Biden said not a single NATO leader expressed reservations about him meeting with Putin but rather have "thanked" him for doing it.

"I had discussions with them about -- in the open -- about what they thought was important from their perspective and what they thought was not important," he said.

Biden and Putin's meeting is slated to begin on Wednesday around 7 a.m. ET and last four to five hours total, with multiple sessions.

The two leaders will first take part in a small session, joined by U.S. Secretary of State Antony Blinken and Russian Foreign Minister Sergey Lavrov, before taking part in a larger working session.

The two leaders are also expected to host dueling, solo press conferences following the summit.

Biden said they weren't holding a joint news conference, as Trump did with Putin, because he didn't want the focus to be on talking time or body language. Doing it this way leaves Putin with less of an opportunity to embarrass the American president, as he's historically tried to do.

"I think the best way to deal with this is for he and I to meet, he and I to have our discussion," Biden said Sunday in England, on another leg of his first trip as president. "I don't want to get into being diverted by, did they shake hands, who talked the most and the rest."

While he is no stranger to Putin, Biden has been intensely prepping for the meeting, receiving at least once-a-day briefings for weeks leading up to the summit.

"He's been preparing for this like he prepares for every significant international engagement. He reviews the issues -- written material; he cares about digging into the details. That very much matters to him," a senior administration official said Tuesday.

The White House has also called on experts to help Biden prep for the meeting -- including Fiona Hill, a top Russia expert and National Security and former Trump administration official who famously said she considered faking a medical emergency to end Trump’s press conference with Putin in 2018 in Helsinki, Finland.

Wednesday's meeting is slated to last four to five hours total, with multiple sessions.

-ABC News' Molly Nagle

Biden arrived in Geneva earlier Tuesday less than 24 hours ahead of his meeting with Putin, scheduled for Wednesday around 7 a.m. ET and expected to last several hours.

Looking to project confidence ahead of the high-stakes summit, Biden didn’t miss a beat during a photo op Tuesday with Swiss President Guy Parmelin.

"Mr. President, are you ready for tomorrow?" a reporter asked.

"I’m always ready," Biden replied.

The meeting with the Swiss president was Biden's final public event for the day.

When the president arrived earlier in Geneva, he was met with a long line of greeters, many dressed in colorful outfits, as he stepped off Air Force One.

The White House said Biden will hold a solo press conference after meeting with Putin, where he will give his takeaways. Putin plans to do the same.

Putin indicated on Friday that he'd be willing to talk about a potential "prisoner swap" between two U.S. Marine veterans, Trevor Reed and Paul Whelan, for Russians being held in the U.S.

Russian officials have indicated they would like to trade Reed and Whelan for two Russians held in the U.S.: Viktor Bout -- one of the world's most notorious arms dealers and dubbed "the Merchant of Death" — and also Konstantin Yaroshenko, a pilot currently serving a lengthy jail sentence for a drug smuggling conviction.

David Whelan told ABC News Live Prime anchor Linsey Davis on Tuesday that his brother, who is manufacturing clothes in a Russian labor camp, is a hostage and that it's difficult to know when that might come to an end.

"I'm always hopeful that he'll be released, but I don't have any idea what the timeline might be," David Whelan said. "The Biden administration has been very outspoken about Paul's case and we've appreciated that as a family. It's given us hope and it's given him hope."

"But he's still a hostage and there's no evidence yet that the Russians are willing to exchange in any exchange for him," David Whelan continued. "They said last week -- the Russian government did — that they would not consider Paul for exchange."

Whelan's family released an audio message from him on Monday recorded from the prison camp in central Russia where he is held. In it, he appealed to Biden to help free him.

"Please bring me home to my family and my dog Flora where I belong. Thank you, Mr. President, for your commitment to returning me home and bringing this deplorable hostage situation to an expedient conclusion," Whelan said in the recording that his family said was made on May 30.

-ABC News' Haley Yamada and Patrick Reevell