Mitsotakis, a Harvard-educated scion of a political dynasty, led his free-market New Democracy party to victory in Greece.
Washington: US President Donald Trump on Tuesday congratulated Greece's new conservative prime minister, Kyriakos Mitsotakis, pledging in a telephone call to keep pursuing the countries' warming relations, the White House said.
"The two leaders expressed their mutual interest in working together and continuing strong cooperation between the United States and Greece," the White House said.
A State Department spokeswoman separately called Greece "one of our closest allies." The United States hopes to work with Mitsotakis to "increase regional stability, boost bilateral trade and diversify regional energy options," she said.
Mitsotakis, a Harvard-educated scion of a political dynasty, on Sunday led his free-market New Democracy party to victory in the country that has started to emerge from economic crisis, ending the four-year rule of leftist leader Alexis Tsipras.
Despite his far-left roots, Tsipras built a close relationship with the United States under both Trump and former president Barack Obama, notably by pursuing warm relations with Israel.
Tsipras also resolved a nearly three-decade row over the name of neighbouring North Macedonia, removing a pestering headache for NATO and Europe but igniting a backlash among Greek nationalists that some analysts say contributed to his defeat.