Cork went eight points ahead before Donal O'Shea got Galway's first score with a free after 14 minutes.
He followed with another free directly afterwards but then Galway failed to clear their lines and Jack Cahalane scored Cork's second goal to lead by 2-05 to 0-02 at the first water break.
A save from Galway goalkeeper Paddy Rabbitte denied Daniel Hogan a third Cork goal, however, they still ended the half leading by 2-09 to 0-05.
Cork had a six-point lead at the second water break but dominated the final quarter.
The win gave them their 13th All-Ireland title overall and put them further ahead in pole position on the all-time roll of honour.