In a statement released in Abuja, Nnamani expressed his gratitude towards his constituents for their unwavering support over the years.
Nnamani, who conceded defeat in the elections, cited irreconcilable differences with the national leadership of the party as the reason for his decision to quit the PDP.
He stated that he had consulted with his associates and constituents before making the decision to resign.
The PDP had previously expelled Nnamani over allegations of anti-party activities and announced their withdrawal from contesting the Enugu East Senatorial District election.
Despite this setback, Nnamani has moved on and hopes that his modest contributions to the development of his constituency will serve as a foundation for his successors to build upon.
In his statement, Nnamani expressed his appreciation for Nigerians, particularly the Ebeano political family, and encouraged them to remain steadfast in the future.
He also reaffirmed his acquaintance with President-Elect Bola Ahmed Tinubu and pledged to continue partnering with him. Nnamani expressed his optimism that a Tinubu administration would prioritize good governance, the rule of law, and human rights for the benefit of all Nigerians.