Mithuben was born in the family of the well-known Parsi Baronet and industrialist, Sir Din-shaw Maneckji Petit on 11 April 1892. Her maternal aunt was a great admirer of Gandhiji, and was the Secretary of the Rashtriya Stree Sabha, established in Bombay. After Gandhiji's return from South Africa, Mithuben often accompanied her aunt on her visits to Gandhiji. She was greatly influenced by his views and principles and decided to join him and help him in his activities. She lived away from her family leading an austere life and she strictly followed the Isha Upan-ishad, Tyen Tekten Bhunjitha. She made it her mission to go to the villages and educate the rural people.
Her Ashram in Maroli was established under the name of Kasturba Vanat Shala. Here children from families of fisher folk, Harijans, Adivasis were admitted and they were taught spinning, carding, weaving, dairy farming, and leatherwork. . In Maroli she started a Diploma course in sewing. She also started mental hospitals for psychiatric treatment. Thirty five thousand patients are treated at the dispensaries set up in Marol, Kevadi and Chasvad. It was at Gandhiji's suggestion that she set up the mental hospital during the Quit India Movement when prisoners in British jails suffered grave physical torture which left them mentally disturbed. She was like a mother to the patients and also to those who worked with her. They addressed her as 'Maiji'. On one corner of the verandah was her office. Her modesty and her sweet loving words won everybody's heart. She always had a never-ending stream of visitors all through the day and all of them left with a glow of happiness on their faces. People in the villages around respected her and almost worshipped her. She sincerely shared their joys and sorrows. Anyone could walk in with a complaint and she would be ready with the remedy. She would send a person to hospital only if her own remedies failed. She had knowledge of medicines, especially of home remedies.
She was an animal lover too. She was seen surrounded by her dogs, cats, and poultry. She loved and nursed them when they were ill. When they died she even buried them with last rites. She named each of her pets and it seemed that she understood their language. She was very generous in treating her guests and she served free meal to anyone who came to her. At first she was cut off from her family fortune but later one of her uncles touched by her spirit of renunciation and zeal for social service gave her a generous amount with which she met her personal expenses.
Her discipline and courage in picketing the liquor shops helped the villagers to rid themselves from the curse of drunkenness.
In her forty-three years of noble service, Mithuben never deviated from her principles. She believed that the secret of success in any endeavor was devotion to duty. One should be true to oneself and be dedicated in ones work She dedicated her entire life for the poor and downtrodden. She is an incarnation of all virtues. All Indians should salute Mithuben for her life of penance and self-sacrifice.