The 72-year-old, who contested the Lok Sabha election from Allahabad in 1984 and won, resigned after three years as an MP.
"Venturing into politics was a mistake. I entered the field in the flow of emotions. But then I realised that emotions are very different from reality in the political arena. So I gave up," the actor said at a session of Agenda Aaj Tak here Saturday.
"I have never thought of going back to politics since then," he added.
The actor was nostalgic while reciting his late father Harivanshrai Bachchan's poem "Madhushala" at the event.
Amitabh noted that his father was teetotaller but his poem was on alcohol and drunkards.
"The poem was written in 1933 and published in 1935. It is amazing that the poem still manages to attract people. My father never drank, but the poem is all about alcohol. It was a hot topic of discussion then," said Amitabh.
"His poems depicted revolutionary thoughts even at that time."
On the professional front, the actor is busy shooting for Bejoy Nambiar's "Wazir". The film also features Farhan Akhtar.