Accra - Professor John Evans Atta Mills was inaugurated as the third President of the Fourth Republic of Ghana by Chief Justice Georgina Theodora Wood on Wednesday.
John Dramani Mahama was also sworn in as the Vice-President of Ghana.
It is the second time that a constitutionally elected President has handed over the nation's highest office to another in the political history of the country.
In his acceptance speech, President Mills promised to heal wounds and unite the country as a whole, adding: "I intend to pursue relentlessly all avenues for entrenching peace and unity in all parts of the country as I am enjoined by the constitution to do."
He said he would be a President for all Ghanaians whether they voted for him or not "and without consideration for which part of the country you come from".
President Mills, who is of the National Democratic Congress (NDC) party, said improving the internal security situation was one of his administrations top priorities so that Ghanaians could begin to feel safer in their homes and communities.
"We will not forget the concerns of the Ghanaian people who want to see an improvement in their living conditions," he assured.
He hoped to uphold the principles of accountability and rule of law, saying: "We have a duty to ensure that our laws are administered without fear or favour."
President Mills also promised to deliver on his campaign message which is investing in people, job creation, infrastructure development and expansion and an open, transparent and accountable government.
He said he would strengthen relations with Ghana's neighbours and help accelerate the processes towards economic integration in the West African sub-region.
Earlier, Ghana's parliament unanimously elected Joyce Bamford-Addo, a former Supreme Court judge, as the new Speaker of Parliament for the fifth Parliament of the fourth Republic of Ghana.
Ms Bamford-Addo, who became the first woman Speaker, was sworn into office by Chief Justice Theodora Wood.
The new Speaker thanked Members of the House for the honour and then in turn, officially swore into office the newly elected Members of Parliament.
