The 89-year-old leader, who arrived at the registry office supported by his wife Ujjwala Sharma and staff members, completed all formalities related to the marriage to give it a legal status.
Tiwari had surprised everyone by marrying Sharma at a simple ceremony at his Mall Avenue residence here.
Tiwari was Chief Minister of Uttar Pradesh thrice and Uttarakhand once. He was the Governor of Andhra Pradesh between 2007 to 2009, when his name figured in a sex scandal and he had to resign.
He was also the External Affairs Minister in the Rajiv Gandhi's cabinet in 1980s. Tiwari was earlier involved in a long legal battle to accept Ujjawla Sharma's son Rohit Shekhar as his biological son.