Mills died last month ahead of a re-election bid and his state funeral was held on Friday.
A military cortege conveyed Mills'ss body from the State House parliamentary complex, where it had lain in state since Wednesday, to the funeral at Independence Square.
More than 10 000 people gathered in and around the huge square heard Ghana's new President John Dramani Mahama laud his predecessor in a funeral oration.
"He entered politics not to amass wealth but to serve people, which he did until his death," said Mahama, the former vice-president.
The cortege later transported Mills's body to the grounds of Osu Castle, the official presidential residence, where he was to be buried with a ceremony that would feature a 21-gun salute and laying of wreaths.
As the motorcade passed through streets on its way to the castle, residents lined the roads to get a glimpse, some crying and others chanting. A number of people climbed trees to have a better view.
'Like a brother'
Among those who viewed the body as it lay under a glass case before the service were Côte d'Ivoire's President Alassane Ouattara and Ellen Johnson Sirleaf of Liberia as well as the leaders of Benin and neighbouring Togo.
US Secretary of State Hillary Clinton, who has been on an African tour and arrived in Ghana on Thursday night, also attended the funeral.
"He was like a brother to me. I will surely miss him," Togo's President Faure Gnassingbe told journalists.
Benin's President Thomas Boni Yayi, also the current African Union chairperson, described Mills as "passionate about peace in Africa and in the region".
His death on July 24 at age 68 following an illness came as a shock to many Ghanaians, despite rumours that he had been sick and reports that he suffered from throat cancer.
Coming just five months ahead of polls in which he was to seek re-election, it upended the presidential race in a country that recently became a significant oil producer and is praised as a stable democracy in an often turbulent region.
Early arrivals had rapidly filled Independence Square, where heads of state and other dignitaries were placed in a special seating area, while large TV screens broadcast the ceremony for those unable to get closer.
The event was also being shown on national TV.
"Today is my saddest day," said Akua Danso, an 80-year-old former teacher who was confined to a wheelchair, being pushed by her grandson.
"I have seen presidents come and go but he was the best. He was very humble. I wish I had the opportunity to meet him while he was alive, just to tell him that he was a gem," she said.
Speaking at the service, Mills's brother Cadman said the gratitude expressed by average citizens since the president's death had brought comfort to the family.
"The testimonials from the ordinary Ghanaians demonstrate that he did his best and that is all that we, as a family, could ask of him," he said.
For a brief period ahead of the start of the funeral, a helicopter hovering over the area dropped leaflets reading, "We want peaceful elections in 2012."
Mahama was sworn in to serve out the remainder of Mills's term hours after his death, as dictated by the constitution.
The new president is expected to be endorsed by the ruling party to run in the December election, which analysts say is likely to be close.
Ghana, a country of some 25 million people, has begun producing oil from its offshore Jubilee field, one of the largest discoveries in West Africa in recent years. The field's operator Tullow has estimated that the field's recoverable resources amount to up to one billion barrels. – AFP