The Ukrainian president said “peace will become closer” after arriving for the conference in Hiroshima on Saturday and later shared an embrace with UK prime minister Rishi Sunak.
Mr Sunak said “good to see you” and slapped Mr Zelensky on the back after they greeted each other with an embrace. “You made it.”
Asked by reporters if it was a good day for Ukraine, Mr Zelensky smiled, nodded and said “thank you so much”.
Leaders at the summit released a statement condemning Russia’s “brutal” war on Ukraine and called it a “serious violation of international law”.
The statement reads: “We once again condemn in the strongest possible terms the war of aggression by Russia against Ukraine, which constitutes a serious violation of international law, including the UN Charter.
“Russia’s brutal war of aggression represents a threat to the whole world in breach of fundamental norms, rules and principles of the international community.
“We reaffirm our unwavering support for Ukraine for as long as it takes to bring a comprehensive, just and lasting peace.
The White House said US president Joe Biden informed his allies at the conference in Hiroshima that it will allow the advanced planes to be donated to Kyiv.
Mr Biden, who is attending the G7 with other members France, Italy, Germany, Japan and Canada, as well as the EU, also announced training for Ukrainian pilots.
Mr Sunak welcomed the decision from the summit, having pressed allies to provide the Ukrainian president with the jets he has been calling for.
Mr Sunak tweeted: “Welcome announcement that the US will approve the training of Ukrainian pilots on F-16 fighter jets.
“The UK will work together with the USA and the Netherlands, Belgium and Denmark to get Ukraine the combat air capability it needs. We stand united.”
The RAF does not have any US-manufactured F-16s. Washington must legally approve their export.
Mr Zelensky is expected to take part in meetings with the G7 on Sunday.
It will potentially bring Mr Zelensky into contact with India’s Narendra Modi and Brazil’s Luiz Inacio Lula da Silva, who have not supported Ukraine like their western allies.
Neither are G7 members, but India is being represented at the summit because it is the current G20 chair, while Brazil has been invited as a guest.
Mr Zelensky’s attendance at the G7, the group that Russia was expelled from over its 2014 annexation of Crimea, is another show of solidarity from western allies.
Japan said he has a “strong wish” to take part in the talks that will influence his nation’s defence against Vladimir Putin’s invasion.
He will also have the chance to pressure and charm India and Brazil into supporting Ukraine.
On Saturday, Mr Sunak met with French President Emmanuel Macron for discussions at the summit and had a short “brush-by” meeting with German chancellor Olaf Scholz.
The Prime Minister had been expected to discuss small boat crossings of the Channel.
Meanwhile, the G7 announced it would establish a new team to root out and counter Russia and China’s use of economic coercion to influence nations’ decisions.