Both Ward's goals came in the first half as Leeds went in at the break with a commanding 4-1 lead.
Leeds maintained their unbeaten start to the season as they took control after only six minutes when Ward put them ahead.
Karen Burke and Rachel McArthur added further strikes before Ward hit her fourth in four games just after the half-hour.
Steph Houghton reduced the scoreline in the 42nd minute, but any thoughts of a fight back were ruined when Sue Smith scored Leeds' fifth 10 minutes after the break before Lucy Dewar hit a late consolation effort for the Black Cats.
This was a fifth successive League win for Leeds who are now just two points behind Arsenal at the top of the table as Sunderland remain second from bottom.