A village cricketer until the age of 20, Jack Brooks made his way through Minor County Oxfordshire and Surrey's second XI before he was signed by Northamptonshire after impressing at a net trial in 2008. He soon slotted into the second XI as an energetic right-arm seamer and competent batsman at No. 8 or 9, and his potential allround value was evident from his very first game for the second XI, in which he cracked 43 and picked up 6 for 99 against Warwickshire. The following year he made his first-class debut against the touring Australians, clean bowling Andrew McDonald and having Mitchell Johnson caught in the slips in the course of one over. His Championship debut a month later was even more impressive, as he picked up 4 for 76 and 1 for 38 to contribute towards a tight, two-wicket win over Derbyshire at Chesterfield. Brooks was given more opportunities in the first XI in 2010, particularly after the departure of Johan van der Wath, and started the season in pleasant circumstance, cracking his maiden first-class half-century against Gloucestershire in April as Northants won by 94 runs.

Jack enjoyed a stellar 2011 season that saw the seamer take 43 Championship wickets at 21 from 10 games. The 26-year-old was called up to the England Lions squad in August as a reward for that form. Brooks is known for his wild wicket celebrations and his trademark headband.