The Victorian key forward was, as expected, picked first when the Giants opted not to bid on highly rated father-son prospect Will Ashcroft.
The Brisbane Lions matched North Melbourne's bid to land midfield gun Ashcroft at pick two.
GWS secured the prized first selection in the 'mega trade' involving former No.1 pick Jason Horne-Francis last month and there was no surprise when they used it on Cadman.
Unlike some other top prospects, the 18-year-old GWV Rebels product has indicated he is fully prepared to move north.
That commitment was attractive to the Giants, who have lost a host of stars back to their home states in recent years.
"It's really exciting. I think it will do good things for me and I like the idea of a re-start, experiencing new things and meeting new people," Cadman said.
GWS recruiting staff told Cadman last week they had committed to selecting him with the top pick.
Only the athletic 195cm forward and his inner circle - his family, manager and junior coach - were in on the secret.
"It's been hard holding it in but it's been well worth it," Cadman said.
"(Being selected at No.1) is really special but at the end of the day it's just a title.
"Obviously there's a bit of pressure added to it, which I don't mind at all.
"I think I'll turn that into motivation and it will make me a better player ... but I'm just here to play footy and do what I do."
Cadman transitioned from a wingman to a key forward during his draft year, leading the NAB League goal-kicking and earning All-Australian selection at the national championships.
He has been likened to former GWS goal-kicker Jeremy Cameron, who mentored the teenager this year, and Carlton's Coleman Medal winner Charlie Curnow.
Brisbane were always committed to drafting Ashcroft, the son of club great Marcus Ashcroft.
He was joined by fellow father-son pick Jaspa Fletcher - the son of Adrian Fletcher - when the Lions matched the Western Bulldogs' bid at pick 12.
North Melbourne had two high-end selections and took Victorian duo Harry Sheezel and George Wardlaw with picks three and four respectively.
Sheezel is set to be the first Jewish player in the AFL in two decades and was subjected to anti-Semitic abuse online during the build-up to the draft.
It will be investigated by the AFL.
Essendon rejected rival trade offers for their first pick, No.5 overall, using it to take highly rated midfielder Elijah Tsatas.
The 18-year-old is the first Bombers player born since the club last won an AFL final, in 2004.
Premiers Geelong used pick eight on local product Jhye Clark, who has been likened to retired flag skipper Joel Selwood, while West Coast selected West Australian pair Reuben Ginbey (nine) and Elijah Hewett (14).
Sydney were denied bids on GWS academy player Harry Rowston (pick 16) and Adelaide father-son prospect Max Michalanney (17), the son of Norwood SANFL great Jim Michalanney.
The Swans then accepted a live trade deal to ship pick 18 to Hawthorn, who used it on bolter Josh Weddle.
Collingwood used pick 19 on Ed Allan, the son of Hawks premiership player and former Fremantle captain Ben Allan.
GWS will have the first pick, No.22 overall, when the draft resumes on Tuesday night.
9°C