The 924-square-foot house, with three bedrooms and four bathrooms, came on the market in the fall at $1.895 million. First constructed in 1946 and later totally rebuilt, the two-story cottage includes vaulted ceilings and a patio with an outdoor shower.
Armstrong, 41, is the lead vocalist, a guitarist and a songwriter for the punk band and also performs with Pinhead Gunpowder. Green Day, which released the albums "Uno!," "¡Dos!" and "¡Tre!" last year, returned to touring last month after a hiatus while Armstrong was in rehab.
Public records show he bought the property in 2006 for $1.699 million.
Kimberly Bibb of HOM Sotheby's International Realty handled the transaction.