Sengstacke is the grandson of late Chicago Defender publisher John Sengstacke.
Police say he approached the security barriers about a block from Obama's home early Tuesday morning and was asked to leave but returned. Investigators say Sengstacke told them he needed to speak with Obama about getting a job.
The Secret Service says no threats were made against Obama or his family.
Police did find a gun and bulletproof vest in Sengstacke's car.
The Sengstacke family released a statement saying they are passionate supporters of Obama and Sengstacke had no intent to harm anyone.
