The case against Frank Kuni came about in May when a New Jersey mother whose door he knocked on recognized him from an online sex offender registry.
He faces up to 16 years in federal prison for lying on government forms, though a shorter term is likely. Sentencing is scheduled for March 2.
Kuni told a federal judge in Camden he gave a false name and birthdate and an altered college student ID card to the Census Bureau because he was desperate to get a job.
Kuni worked for the Census for a few days before he was fired for the lies and his history as a sex offender.