In a state where the Communists made history by coming to power for the first time through the ballot box anywhere in the world, Karunakaran was the undisputed leader of the rival Congress in Kerala for four long decades, a veteran without whose blessings no one could grow in the party.
Born in Kannur July 5, 1918, Karunakaran started off as a political activist after his school days, tasting his first electoral victory two years before India became independent. That was in 1945 when he was elected to the Trissur Municipal Council in 1945 on a Congress ticket.
Since then, Karunakaran has held every political position -- legislator (elected seven times consecutively from Mala in Trissur, from 1967 to 1991), minister, leader of the opposition thrice, chief minister four times, elected to the Rajya Sabha thrice and to the Lok Sabha twice.
The only position he did not take up was that of governor though he was offered more than once in the winter of his political career. He turned it down saying he always preferred to be in the limelight.
Congress was his passion and first love. He was one of the very few party leaders who had excellent relations with Nehru, India's first prime minister, and he became one of the trusted men of Indira Gandhi, Nehru's equally powerful daughter.
A man who loved power, Karunakaran used his closeness to Indira Gandhi to run down his rivals, which at one time included the present Defence Minister A.K. Antony.
In the process, no Congress leader could even dream of making it big in Kerala unless he was on the right side of Karunakaran.
A master political craftsman, Karunakaran -- his critics maintained -- ensured that the Congress was never united in the state. He divided the party between himself and Antony.
He groomed more than three dozen Congress leaders who currently owe their status to him. They include state Congress president Ramesh Chennithala, G. Karthikeyan, V.M. Sudheeran and P.P. Thankachen.
Even when his detractors grew in number, he was always one step ahead of others.
His first major setback came when he had to resign as chief minister a month after taking charge following a judicial stricture over the death of a young man accused of being a Maoist, post-Emergency.
The disappearance of Rajan, the engineering college student, haunted Karunakaran for the rest of his life.
He had to quit as chief minister again in March 1995 when his name was linked to a police official, Raman Srivastava, in what was known as the "ISRO spy scandal".
By then his detractors were aplenty, the chief reason being his love for his son K. Muraleedharan, who took to politics after failing in business.
Quitting state politics, Karunakaran moved to Delhi and became the industry minister in the cabinet of P.V. Narasimha Rao. By now, Antony had become a strong rival. This unsettled the veteran.
But Karunakaran still retained clout in Kerala. He gifted the post of state Congress president to his son as part of a deal that saw Antony become the chief minister in 2001.
However, Karunakaran never spared a chance to unsettle Antony. He even supported the Left in a Lok Sabha election.
Then, he dramatically dumped the Congress and formed his own party in May 2005, with the intention of crossing over to the Left, for long his sworn enemy.
But he made a hasty retreat to the Congress-led United Democratic Front (UDF). It did not help. All but one of the 17 people who contested as his candidates in the 2006 assembly polls lost.
A disgruntled Karunakaran merged his party with the Nationalist Congress Party (NCP), a Left ally. But the Left not only said 'no' to him, but also booted out the NCP from its ranks.
A humiliated Karunakaran returned to the Congress. But his son refused to follow suit and renounced all ties with his father.
Karunakaran then went into hibernation. His health deteriorated further. He was deeply hurt when his son did not greet him when he turned 90.
Since then he had been more or less confined to his home but made it a point to grace the Congress party office on important occasions -- and was in touch with his well-wishers.
In the end the banyan tree looked like a sad loner, his political legacy in tatters.