Educated, according to Anthony Wood at Exeter College, Oxford (though he did not take a degree), he later studied law at Lincoln's Inn.
Hakewill became Member of Parliament for Bossiney in Cornwall in 1601, probably nominated for the seat by its patron, his maternal uncle Sir William Peryam, Lord Chief Baron of the Exchequer.
Described by the antiquarian Anthony Wood as "a grave and judicious counsellor" but "always a puritan", Hakewill was a friend of William Prynne and an associate of John Selden whose critical views on the royal prerogative he shared.
Her elder half-sister Ann was the third wife of Sir Julius Caesar, Master of the Rolls, to whom Hakewill addressed gratulatory Latin verses (now in the British Library).
In the latter part of his life Hakewill lived at The Hale in Wendover, Buckinghamshire and was survived by at least two sons, William and Robert.