A door operator having an automatic roller closes and opens a door attached to a doorjamb by a door hinge. The roller is actuated by a motor and housed within a protective roller casing affixed to the bottom of a door. The door operator may be integrated with a smart home, thereby allowing a user to close and open a door by voice command. The door operator may be retrofitted to existing doors. A door may also be modified such that only a magnet holds the door closed and a closed position such that the smart home door closing apparatus may be used to open a door. The roller may translate between an extended position engaging the floor below a door and a retracted position above the floor, either inside or adjacent to the door itself.