Nominated as its candidate by the United Progressive Allaince, whose troubleshooter he has been for the last eight years, the 77-year-old leader from West Bengal 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.
Ever seen as the perennial 'No 2' in the Congress, on whose ticket he became a Rajya Sabha member for the first time in 1969, Mukherjee may have missed becoming the prime minister on a couple of occasions, but still he was the man to whom the government looked to during times of crisis.
Even his nomination as a candidate for the President's election, and sparing him from the government, has come after a huge dilemma for the Congress president Sonia Gandhi, who trusted him as a deft manager of the government that has often moved from crisis to crisis in both the versions.
Of course, Mukherjee had his own bad days in the Congress when he had to quit in the mid-'80s after he had evinced an interest in becoming the prime minister on 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, who was elected to Rajya Sabha in 1969, was for a long time a member of the Upper House before his first direct election to Lok Sabha in 2004 from Jangipur in West Bengal. He repeated his victory in 2009 but had expressed a desire not to contest elections again in view of his advancing age.
Mukherjee was a powerful minister of state for revenue during the Emergency and in nine years from 1973, he rose to become the finance minister in Indira Gandhi's Cabinet.
Again, his importance was seen when the late PV Narasimha Rao made him deputy chairman of the Planning Commission as well as minister for 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.
His profile on the Lok Sabha's website says Mukherjee 'was considered top-ranking minister and presided over the Cabinet meetings of the Union in the absence of the prime minister during 1980-85'.
Son of 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 be became a member of the Rajya Sabha.
Recording a quick growth in his political career soon after, Mukherjee, who became a minister of state for industrial development in 1973 rose to become the country's finance minister (1982-84) during Indira Gandhi's regime, a post which he held again in UPA 2 under Prime Minister Manmohan Singh.
Ironically it was this phenomenal career growth of Mukherjee, which also became a cause of his much-talked about stagnation in politics, so much so that became finance minister again in UPA 2 after around 30 years.
Mukherjee was leader of the Rajya Sabha from 1980-85. Currently he is the leader of Lok Sabha, while Prime Minister Manmohan Singh is the leader of the Upper House.
When Mukherjee was finance minister of the country, Manmohan Singh was appointed a RBI governor in 1982.
In what could be described a case of chasing each other's shadow, Singh became deputy chairman of Planning Commission from 1985 to 1987, a post Mukherjee later held from 1991 to 1996, when Singh became Finance Minister under PV Narasimha Rao.
Mukherjee also had a brief stint as chairman of the Economic Advisory Cell of the All India Congress Committee between 1987 and 1989. Interestingly, Manmohan Singh also held this post, when the Congress was out of power between 1999 and 2004.
Mukherjee, who started his career as a college teacher, always carried the traits of a teacher, never hestitating to give a reprimand or two to juniors whether in his party or Opposition.
Mukherjee was also jocularly called 'GoM Mukherjee' in political circles as he headed close to 33 Group of Ministers on various topics.
Mukherjee has five books published to his credit on political and economic issues and under his editorial guidance, the history of Congress was published in which there was a candid admission of excesses during the Emergency.
He got the Best Parliamentarian Award in 1997. Ten years later, the Padma Vibhushan followed for him in 2007.
In the Congress party, Mukherjee became AICC treasurer in 1978. Journos and AICC media department officials still recall Mukherjee's tenure as the media department chairman of the party. Mukherjee was AICC general secretary in 1998-99.
In 1984-91, 1996 and 1998, Mukherjee was chairman of the campaign committee of the AICC for conducting national elections to Parliament, besides being a member of the Congress Working Committee and Congress Election Committee.
In government, Mukherjee held all the key portfolios including defence from May 2004 to October 2006 and external affairs from October 2006 to May 2009, besides the finance portfolio, which he held again in 2009 after a gap of 27 years.
In the past, he also held portfolios like commerce and steel and mines, revenue and banking (independent charge), shipping and transport, industrial development, commerce and supply -- besides presiding over a number of parliamentary committees.