Odinga promised to help people who lost their jobs or homes during the country's post-election violence, which took the lives of about 1,500 people and forced about 600,000 out of their homes, the BBC reported.
"You have seen the ugly face of ethnic confrontation in our country. I feel confident that the experience we have gone through has been a teacher and everyone is going to ensure that this coalition does succeed," Odinga said.
Many Kenyan citizens reportedly celebrated the power-sharing agreement between Odinga and Kibaki.
The government and opposition were set to resume negotiations concerning long-term ownership of land, the constitution and the economy Friday.