Speaking at the airport in the former capital of Yangon, Campbell said the US "reaffirmed our commitment to a dialogue among the government, the opposition and ethnic groups."
The goal of such a dialogue, he added, "would be national reconciliation and a fully inclusive political process in Burma".
Later, speaking to reporters after his arrival in Tokyo, he said his visit to Myanmar was a "first step" in improving relations with Myanmar's military rulers.
|Aung San Suu Kyi welcomed renewed US engagement with Myanmar [AFP]
Campbell and his deputy, Scot Marciel, are the highest-ranking American diplomats to visit Myanmar, also known as Burma, since 1995, when Madeleine Albright, the then-UN ambassador, made an official visit.
Details of Campbell's talks with Aung San Suu Kyi were not revealed, but the meeting offered the Nobel laureate her first trip in years outside the confines of her home and a nearby government guesthouse, where she has met UN and government officials in the past.
The 64-year-old has been detained for 14 of the past 20 years, mostly under house arrest and for shorter periods at the Insein prison in Yangon.
Aung San Suu Kyi also welcomed new US moves to engage with Myanmar's military government.
In late September she wrote a letter to Myanmar's top ruler, Senior General Than Shwe, to offer her co-operation in getting Western sanctions lifted after years of backing harsh measures against the ruling generals.
The generals granted the Nobel peace laureate two rare meetings with a government minister and allowed her to meet Western diplomats last month.
Thein Sein, Myanmar's prime minister, told Asian leaders at a summit in Thailand last month that the government sees a role for Aung San Suu Kyi in fostering reconciliation ahead of the promised elections next year, but it was not clear what form this would take.