Dropping the Max Beesley-fronted TV ads was led by marketing director Sophie Relf, who brought in Kaper on a retainer in November to handle trade PR.
"We believe that our key audience of young people skip TV ads," Relf told PRWeek. "We needed to change to owned, earned and shared media. Kaper impressed us hugely because it fully understands that audience and its influencers."
Kaper has been working alongside another freshly appointed agency, Seven, which is responsible for content marketing.
"Kaper's role is to look at business to business PR opportunities where we could talk about the changing ways in which people jobseek and the changing focus of jobseekers," Relf said.
A joint agency meeting hosted by Google and including Jobsite's digital media agency iProspect produced the idea of a video spoofing The Apprentice, called Jobsite Advantage.
"We had a plan that we needed to engage with the 'millennial' audience [people under 35] and particularly on Boxing Day, when people are bored and playing with their new tablets and mobiles."
Relf claimed early results were "fantastic" because Jobsite has taken a 7.5 per cent share of voice from its competitors, which include Monster, Totaljobs and Reed on careers topic mentions across UK social media and blogs.
Donna Amato, business director at Kaper, said: "Jobsite has changed its focus because online traffic did not convert into quality job applicants. We will be targeting a younger group of job seekers and provide recruiters and candidates with a hub of online activity for different sectors."