She was born Jane Griffin, the daughter of a well-to-do silk merchant in London. Her mother died when Jane was three and she and her two sisters had a rather indifferent boarding-school education. However, she loved study and collecting facts and recorded the results of her curiosity in long diary entries.

The family travelled widely and over the years she had many suitors but she was determined to man for love. In 1823 one of her friends married the arctic explorer, Captain John Franklin, but died eighteen months later leaving a baby daughter, Eleanor. Franklin was a friend of the Griffin family and spent much time with them after his wife's death, marrying Jane in 1828 when she was thirty six.

After their honeymoon in Paris, Franklin was knighted for his exploration exploits and appointed to a naval position in the Mediterranean. Jane found her stepdaughter difficult and preferred to travel and explore, spending occasional time with her husband. She persuaded Franklin to decline an appointment as Lieutenant-Governor of Antigua but supported his acceptance of the position of Lieutenant-Governor of Van Diemen's Land at twice the salary.

Jane saw herself as responsible to guide the infant colony into development, particularly cultural and intellectual. Her first approach was to see as much of the island as possible. Amongst many contributions she bought land at Lenah Valley for a botanical garden and built a glypothek, a small Greek temple, for a museum and library. She founded Christ College as a secondary school for boys. She tried to help female convicts but with little success. She adopted an aboriginal girl, Mathinna, whose parents had been killed. She helped poor farmers in the Huon, in the area now known as Franklin, by buying land along the river which she divided into farms for poor families to whom she provided rations and implements. She instigated the Hobart Regatta. She offered a shilling a head for every snake killed, paying more than 600 pounds. She presented Betsey Island to the people of the colony and was the first woman to climb Mount Wellington.

She visited both Flinders and Maria Islands and made a memorable trip to the west coast when she was carried in a sort of palanquin for the first thirty miles. Because of delays and bad weather, the planned eight-day trip took twenty-one.

Some of Sir John's problems may have stemmed from his wife's interference although most of them were partly caused by criticism from the Montagu's who were supporters of the previous incumbent, Arthur. Sir John's replacement arrived before he had been notified of his recall and he was not offered further employment on their return to England. He took command of the search for the Northwest Passage in 1845. Lady Jane was wracked with anxiety when by 1848 there was no news of him, seeking finance for a search in Tasmania, the United States and elsewhere.

When it was clear that Sir John had perished, Jane, now 58, spent much of her time travelling. She died at the age of 84 in July 1875.