Trelawney was the son of Robert Trelawney who was three times mayor of Plymouth. He was a merchant at Plymouth and a colonist. On 1 December 1631 Trelawney and his partner Moses Goodyeare were granted a patent by the Plymouth Company for a tract of land between Spurwink River and Presumpscot River and for Richmond's Island at Cape Elizabeth, Maine. In 1633 Trelawney was Mayor of Plymouth. He built Ham House near Plymouth in 1639.
In April 1640, Trelawney was elected Member of Parliament for Plymouth for the Short Parliament. He was re-elected in November 1640 for the Long Parliament but was expelled from the House of Commons in March 1642, and committed to prison for publicly stating that the Commons had no power to appoint a guard for themselves without the King's consent.
- William Durkee Williamson The history of the state of Maine: from its first discovery, Volume 1
- Plymouth Council - List of Mayors
- This is Plymouth Ham House
- Willis, Browne (1750). Notitia Parliamentaria, Part II: A Series or Lists of the Representatives in the several Parliaments held from the Reformation 1541, to the Restoration 1660 .... London. pp. 229–239.
- Robert Burke A genealogical and heraldic history of the commoners of Great Britain Volume 4
|Parliament of England|
Parliament suspended since 1629
|Member of Parliament for Plymouth
With: John Waddon
Sir John Yonge, 1st Baronet