These characters are unlocked during the career mode after you complete their sponsorship challenges.

Character	How to unlock
Chris Haslam	Complete the Almost sponsorship challenge in career mode.
Danny Way	Complete the Plan B sponsorship challenge in career mode.
Eric Koston	Complete the Lakai sponsorship challenge in career mode.
Jake Brown	Complete the Blind sponsorship challenge in career mode.
Lucas Puig	Complete the Cliche sponsorship challenge in career mode.
Mike Carroll	Cmplete the Girl sponsorship challenge in career mode.
Rob Dyrdek	Complete the Alien Workshop sponsorship challenge in career mode.
Terry Kennedy	Complete the Baker sponsorship challenge in career mode.