Spencer was the second son of
Robert Spencer, 1st Baron Spencer of Wormleighton, and his wife, Margaret Willoughby, and was baptised on 4 January 1591 at
Brington, Northamptonshire. He matriculated at
Magdalen College, Oxford with his elder brother John in October 1607. In the autumn of 1610 he traveled to France with his brother. On John's death at Blois in 1612, he became the heir to the barony. He became a
Member of Parliament for
Brackley in 1614, but left no trace in the records. As the member for
Northamptonshire (1620–1622 & 1624–1627) he was an active participant in parliamentary sessions. From 6 May 1618 to 1621, Spencer held the office of Deputy Lieutenant of Northamptonshire. On 25 October 1627, he succeeded his father as 2nd
Baron Spencer of Wormleighton. == Family ==