Marc Grossman's visit comes as U.S.-Pakistani relations are at a low point due to the dispute over an American CIA contractor who shot dead two Pakistanis.
Washington says the man, Raymond Allen Davis, has diplomatic immunity and acted in self-defense against robbers. Pakistan has resisted releasing him, saying the matter is up to the courts.
The U.S. Embassy said Grossman met late Sunday with finance minister, Abdul Hafeez Sheikh.
Grossman, who was appointed to the post in February, also was to meet Pakistani Prime Minister Yousuf Raza Gilani, President Asif Ali Zardari and other top officials Monday, said Alberto Rodriguez, spokesman for the U.S. Embassy in Islamabad.