Mr Guy's wife Kylee Guy cried out "he killed my husband'' in tears and left the courtroom. Macdonald was tearful as the verdict was given.
His wife Anna Macdonald, Mr Guy's sister, held onto her father Bryan Guy's arm and cried as the verdict was delivered.
Macdonald's parents, Kerry and Marlene Macdonald, sat on the opposite side of the court, behind the dock.
Justice Simon France remanded Macdonald in custody for a callover in Palmerston District Court on July 31.
The callover is to set a sentencing date for other charges, including arson and criminal damage, to which Macdonald earlier pleaded guilty.
The Crown alleged Macdonald shot and killed Mr Guy, 31, at the end of the driveway of his Feilding home in the pre-dawn darkness of July 8, 2010.
Macdonald, 32, denied murder.