Cotterell’s grandfather owned manorial property in Norfolk by 1511. Cotterell himself acquired by marriage in 1606 a small property in Lincolnshire, later estimated to be worth £160 a year.
Cotterell subsequently entered the service of the rising royal favourite George Villiers, who described him as ‘one of whose honest and civil carriage I have had long trial’ when he obtained for him the post of muster-master of the Buckinghamshire militia in 1617.
In 1620 Buckingham, now lord admiral, appointed Cotterell vice admiral of Lincolnshire. The post gave Cotterell sufficient local standing to be returned to the third Jacobean Parliament for Grantham, a borough some eight miles from Wilsford. He was nominated to only one committee, on preparing the petition against recusants (15 Feb. 1621).
In July 1628 Cotterell was granted £5,000 as royal bounty.
