The 26-year-old, who was not retained at Sixfields at the end of his two-year contract, played for the Hawks in their friendly against Brighton at the weekend.
Whitehawk manager Darren Freeman, who has led a summer-long pursuit of Robinson, believes the ex-Cobbler could make a huge impact at the Enclosed Ground.
And Freeman was delighted to secure the services of a player who was a regular in the Town team towards the end of 2012.
“My attitude is if you don’t ask, you don’t get,” he said.
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“I have targeted players this summer who some people would think would cost fortunes and wouldn’t join us but that is not always the case.
“Jake has been a professional footballer for a long time, firstly with Albion and then for a number of seasons away from Sussex.
“He has had offers from teams in the north this summer but he wanted to come back home where he could play week in, week out and start to enjoy his football again.”
Robinson’s move to Whitehawk means that three of the players released at Sixfields last month have now found new clubs.
John Johnson, Lewis Wilson and Paul Turnbull are yet to sign elsewhere, while Nana is training with Yeovil Town and Adebayo Akinfenwa and Louis Moult have joined Gillingham and Nuneaton respectively.