Washington "supports the important work of the ICTY and respects its ruling," a State Department spokesman said, referring to the verdict of the International Criminal Tribunal for the former Yugoslavia based in The Hague.
"We will continue to commemorate the victims of the horrific crimes committed in the former Yugoslavia," the spokesman added.
"We urge the countries and peoples of the region to refrain from divisive rhetoric and work together to build a better future for the entire region."
Mladic, known as the "Butcher of Bosnia," was found guilty by the UN judges on 10 counts including genocide, war crimes and crimes against humanity such as murder and deportation.
He was however acquitted of one charge of genocide in certain municipalities.
About 100,000 people were killed and 2.2 million displaced in the 1992-1995 war when ethnic rivalries tore Yugoslavia apart.