"We made no secret about the fact that he wasn't doing it as a volunteer and he has done this work for previous Labor governments as well.
"This is about getting young people into trades. He is a high profile person involved in the media industry and you have to meet the market."
Cam's $345,000 paycheck was revealed in a Senate estimates hearing on Thursday.
Department of Employment and Skills officials told the hearing Cam would be paid $260,000 in this financial year and $85,000 in 2020-21.
It comes after SBS News submitted a freedom of information (FOI) request for the payments but was told it is "still being processed".
Cam's taxpayer-funded role will see him work with the National Careers Institute, alongside government, industry, education providers, career advisers, parents and employers to improve career options.
The Gold Logie winner will highlight how practical and technical training can lead to high-paying jobs.
His appointment was announced by Employment Minister Michaelia Cash in August, but the government would not reveal his pay at the time.
With additional reporting from AAP