What is the name of Paulie Walnuts' real surname?

Paulie Walnuts' real surname is Gualtieri. His full name is Peter Paul Gualtieri, and Tony Sirico played him throughout The Sopranos.

Paulie begins the series as a soldier in the DiMeo crime family and later becomes a captain. He is one of Tony Soprano's oldest and most trusted associates, although his paranoia, gossiping, and obsession with old-fashioned mob etiquette frequently create problems.

The nickname “Walnuts” comes from an early hijacking incident involving walnuts, not from Paulie's surname or family background. Another common mix-up is confusing him with Salvatore “Big Pussy” Bonpensiero, Christopher Moltisanti, or members of the Soprano family; Gualtieri is specifically Paulie's family name.

Paulie's biological family history is also unusually complicated. Nucci Gualtieri, whom he believes is his mother for much of the series, is actually his biological aunt. The character's surname was reportedly inspired by real-life DeCavalcante crime-family mobster Frank Gualtieri.