Marcellus Chambers pounced on Penn in the early hours of 20 April, 2010 in Washington, D.C. and stole the star’s wallet and two cell phones.
The actor, who was working as a liaison officer for President Barack Obama at the time, filed a police report immediately after the incident and Secret Service agents became involved when it emerged one of the phones taken in the robbery was the property of the U.S. Government.
Chambers pleaded guilty to the charges on Tuesday (05Apr11) and is now facing up to four years in prison for the felonies. Other counts stemming from the attack were dropped as part of a plea deal with prosecutors, according to TMZ.com.
He will be sentenced on Thursday (07Apr11).
Penn quit hit TV drama House in 2009 to take on a government role as Associate Director of Public Engagement, working on building relations between the White House and Asian communities.
He briefly left the post early last year (10) to reprise his stoner character Kumar in yet-to-be-released festive film A Very Harold & Kumar Christmas, but returned to Washington, D.C. in November (10) to resume his political career.