A Brooklyn prosecutor was busted early Saturday on a drunken driving charge.

Assistant DA Chrismy Sagaille, 31, was pulled over about 4 a.m. after cops saw him run a red light at East 85th Street and Flatlands Avenue in Canarsie, police said.

Sagaille reeked of booze and had bloodshot eyes, police sources said.

Cops cuffed him when he refused a Breathalyzer test. He was charged with a DWI and traffic device violation.

Sagaille has two prior arrests that are both sealed, police said.