[5] Ferrar was elected treasurer—effectively deputy governor—to Sir Edwin Sandys on 23 April 1619 and went on to play a significant role in the Virginia Company.
Sir Edwin Sandys, John Ferrar and his brother Nicholas made changes that resulted in the growth of the Virginia colony from 1,000 people in 1618 to over 2,200 in 1619.
The birth of representative government in the United States can be traced from this “Great Charter” as it provided for self-governance from which the House of Burgesses and a General Council appointed by the Governor were created.
[11][12]: 57 During the English Civil War, Ferrar gave refuge at the Little Gidding community to Charles I, pursued by Cromwell's roundheads, but soon realised that his house was sufficiently well known to draw the parliamentarians' attentions.
[4]: 227 Ferrar wrote a full-length life of his brother Nicholas, which was never, however, published, and only part of which survives in a copy made by the 17th-century antiquarian, Thomas Baker.