[2] Cardwell began his playing career with the North Brunswick CYMS and won their best and fairest award.
Cardwell enlisted to the Australian Army on 23 December 1941 in Caulfield to fight in World War II.
[2] At one point during his service, when he was on leave, Cardwell was given an opportunity to make his senior VFL debut for the Demons, but he instead decided to take a honeymoon with his wife, Mavis.
[3] Cardwell, saying he was "hooked on football",[3] accepted the job and gave up his engineering business,[3] thereby becoming the first full-time secretary in the VFL.
[3][6] Although Cardwell often clashed with Smith, who he had recruited from Fitzroy,[3] and who went on to become the AFL Coach of the Century, they were close friends.
[3] He was considered the greatest Australian rules football talent scout of his era, with the success that Melbourne had during his employment a testament to his recruiting prowess.
[10] Cardwell recruited many of Melbourne's premiership greats, including Laurie Mithen, John Beckwith, Frank Adams, Brian Dixon, Athol Webb, Tassie Johnson, Ian Ridley, Bob Johnson and Hassa Mann.