During a visit to Budapest on Monday, Rubio emphasised the strong personal relationship between the nationalist leader and US President Donald Trump.
Orbán, who has led Hungary since 2010, is one of Trump's most vocal supporters in the European Union and has actively curried the US president's favour leading up to the April 12 vote in which he will face the toughest challenge of his last 16 years in power.
Rubio was in the Hungarian capital for meetings with Orbán and his government, where he signed an agreement on US-Hungarian civilian nuclear cooperation.
This includes the possible purchase of compact nuclear reactors — known as small modular reactors or SMRs — as well as US-supplied nuclear fuel and spent fuel storage technology.
At a news conference in Budapest, Rubio said US-Hungary relations — which both he and Orbán described as experiencing a "golden age" under Trump — go beyond mere diplomatic cooperation.
"The prime minister and the president have a very, very close personal relationship and working relationship, and I think it has been beneficial to our two countries," Rubio said.
"President Trump is deeply committed to your success because your success is our success."
Rubio's stop in Hungary followed a visit to Slovakia on Sunday after he previously attended the Munich Security Conference in Germany.
Led by eurosceptic populists who oppose support for Ukraine and vocally back Trump, Slovakia and Hungary are both friendly territory for Rubio in his push to shore up energy agreements with both central European countries.
Widely considered Russian President Vladimir Putin's most reliable advocate in the EU, Orbán has maintained warm relations with the Kremlin despite its war against Ukraine.
Orbán has also built ties with Trump and his MAGA movement — short for the 2016 Trump campaign slogan "Make America Great Again".
He has remained firmly committed to purchasing Russian energy despite efforts by the EU to wean off such supplies and received an exemption from US sanctions on Russian energy after a November meeting in the White House with Trump.
Rubio would not specify on Monday how long that exemption would last as the EU plans to phase out Russian fossil fuels entirely by the end of 2027.
Apparently trusting that his political and personal affinity with Trump could pay even greater dividends, Orbán and his government have sought to woo the US leader to Hungary before the pivotal April elections — hoping such a high-profile visit and endorsement would push Orbán, who is trailing in most polls, over the finish line.
On Monday, Orbán told Rubio that his government is ready to host any future trilateral peace summit between the United States, Russia and Ukraine, and that Trump has an "open invitation" to Budapest.
He also claimed that Ukraine and its president, Volodymyr Zelenskiy, were seeking to interfere in Hungary's upcoming elections by criticising Orbán's opposition to providing weapons or financial aid to Kyiv and threats to block Ukraine's eventual membership in the EU.
Many in MAGA and the broader conservative world view Hungary as a shining example of successful conservative nationalism, despite the erosion of its democratic institutions and its status as one of the EU's poorest countries.
Orbán has riffed on Trump's popular slogan and declared that he and his movement seek to "Make Europe Great Again".