Emily Lewis, from Aberdeen, and Dominic Hartley, both 21, were killed in Warrensburg, New York, on June 24 when they were struck by a Ford Escape SUV driven by Peter Goldblatt.
Warren County Court, in Lake George, New York, heard Goldblatt, 40, who worked at his parents' golf course, had 110 microgrammes of alcohol in 100 millilitres of blood when he was tested. The legal limit in the US is 80 microgrammes.
The jury took four hours to find Goldblatt guilty of all the charges he faced.
These included aggravated vehicular homicide, vehicular manslaughter in the first degree, manslaughter in the second degree of Emily Lewis, manslaughter in the second degree of Dominic Hartley, reckless driving and driving while intoxicated.
Warren County district attorney Kate Hogan, who prosecuted Goldblatt during the trial, said: "The uncontroverted testimony at the trial established that this defendant was drinking beer throughout the evening of June 24.
"He drove drunk and ploughed into a group of kids who were innocently standing on the side of the road. The jury's verdict reflects the overwhelming evidence in this case.
"While the verdict is gratifying, it does little to assuage the grief of the Hartley and Lewis families."