He was the son of William and Margaret (Chandler) (Monck) Denison. He married first Bridget Thompson and second Ann Borodell.
George Denison died in Hartford, Oct. 23, 1694, while there on some special business, being 76 years old. His wife, Ann Borodell, died Sept. 26, 1712, aged 97 years. They were both remarkable for magnificent personal appearance, and for force of mind and character. She was always called "Lady Ann." They held a foremost place in Stonington. At the time of their marriage, in 1645, she was 30 years old and he 27. He has been described as "the Miles Standish of the settlement," but he was a greater and more brilliant soldier than Miles Standish. He had no equal in any of the colonies, for conducting a war against the Indians, excepting, perhaps, Captain John Mason.
George's brother, General Daniel Denison wrote in 1672: " My Brother George buried his first Wife in the year 1643, went to England, was a soldier there about a year, was at the Battle of York or Marston Moor where he did good service, was afterward taken prisoner, but got free, and having married a second Wife, he returned to New England the year before our Mother died, and not long afterward removed himself to New London, near whereunto at Stonington he now liveth."
The story is that George met his second wife, Ann Borodell, when he was wounded and took shelter in her father's house. He married her in England and returned to Massachusetts about 1644.