He was sworn in as Governor of the oil producing state on 29 May 2007, taking over from Dr.
Peter Odili (also a member of PDP).In June 2007, Shell Petroleum Development Company announced a plan to relocate its headquarters from Port Harcourt to Lagos for security reasons.
Omehia appealed to the people to help fight against hostage takers, who were harming the state economy.
In September 2007, Celestine Omehia won approval for a supplementary state budget of N53.2 billion in addition to the approved 2007 budget of N179 billion.
The supplementary budget was almost entirely earmarked for capital projects.
Tell Magazine stated that Omehia may have been under pressure to settle "election liabilities".On 25 October 2007, the Supreme Court annulled Omehia's election, ruling that Chibuike Amaechi, not Omehia, was the PDP's legitimate candidate.
Amaechi had won the PDP primaries, but the party had substituted Omehia at the last moment due to allegations of graft.
In October 2009, Omehia asked the supreme court to review their opinion.