Reaching the pinnacle of his career and away from the hurly-burly of politics, the 76-year-old Congressman from West Bengal, often called a 'man for all seasons", is variously described as a walking encyclopedia, chronicler of Congress history, expert in matters of the Constitution and governance and a stickler for rules in Parliament.
Renowned for his negotiation skills, the UPA's little big man was till recently the troubleshooter of the ruling alliance, a task Mukherjee handled for the last eight years.
The seasoned politician will now bring to the top Constitutional post his rich and varied experience Fondly known as 'Poltu' in his younger days, it has been a long journey for Mukherjee, from a humble village in West Bengal, to the seat of power in Raisina Hill and he could assume a crucial role in the next general elections.
Not an established lawyer by training but considered an expert in the working of the Constitution and governance, he was ever seen as the perennial 'No 2' in government.
Mukherjee, who will be away from the rough and tumble of politics, was a utility man from the days of Indira Gandhi, when he was the powerful Minister of State for Revenue during the Emergency, and later as Finance Minister in the 80s.
He was also the External Affairs Minister in the 90s. His rise had been steady and such valuable was his contribution to government that his nomination as a Presidential candidate came after a huge dilemma for Congress party, which heads the UPA coalition that has moved from crisis to crisis in the last eight years.
The veteran leader, known for his razor sharp memory, had become a Rajya Sabha member for the first time in 1969. Mukherjee was for a long time member of the Upper House before his first direct election to the Lok Sabha in 2004 from Jangipur in West Bengal.
He repeated his victory in the 2009 elections but had expressed a desire not to contest elections again in view of his advancing age. Mukherjee was a top ranking minister and presided over Mukherjee was a top ranking minister and presided over the Union Cabinet meetings in the absence of the Prime Minister during 1980-1985.
Of course, Mukherjee had his own bad days in Congress which he had to quit in the mid 80s after he had evinced interest in becoming the Prime Minister after the death of Indira Gandhi in 1984.
It took some time before he came back into the party but once he was in, there was no stopping his rise once again. Mukherjee became Finance Minister again in 2008 after P Chidambaram was shifted to Home Ministry in the wake of 26/11 Mumbai terror attacks.
Again his importance was seen when PV Narasimha Rao made him Deputy Chairman of the Planning Commission as well as Minister of External Affairs. In between he had to quit because he ceased to be a member of Parliament and came back to the Cabinet after re-election.
Mukherjee started his public life in the 60s in Bangla Congress during the time of late Chief Minister Ajoy Mukherjee of the United Front government when Jyoti Basu was Deputy Chief Minister in West Bengal.
He was general secretary of Bangla Congress. A post-graduate in political science and history, he can recollect any event of historical importance or mundane political and other events, a matter of envy to many of his colleagues.
Son of a senior Congress leader Kinkar Mukherjee from West Bengal, Pranab had a brief stint as lawyer, teacher and journalist before he was embedded to his destiny of politics in 1969, when he became a member of Rajya Sabha.