He was speaking following his release from the Suranaree Camp of the 2nd Army in Muang Nakhon Ratchasima district of Nakhon Ratchasima province on Thursday evening after six days in detention.
Reunited with his 82-year-old mother, his brother and other close relatives who were waiting there to greet him, Mr Suporn said he realised that everyone should cooperate in the attempt to solve the national crisis and prevent the possibility of civil war.
With this awareness, he had decided to end his involvement in civil action, resign his membership of the Pheu Thai Party and quit politics.
He said he would return to an ordinary life and take good care of his mother and family.
Mr Suporn has been a key leader of the red-shirt United Front for Democracy against Dictatorship (UDD) that supports fugitive former prime minister Thaksin Shinawatra.
He had earlier vowed to build up a force of 200,000 soldier-like civil warriors to fight against the People's Democratic Reform Committee, led by former Democrat Party MPs, that was campaigning in the streets against the former government of Yingluck Shinawatra, a younger sister of Thaksin.
The National Council for Peace and Order had summoned Mr Suporn to report for discussions after the coup on May 22. He was then detained for six days.