Well it depens on which invasion ur looking for.

Ike

Ike came up with the plans (OVERLORD) and issued the orders to attack. His sense of timing was crucial.
But make no mistake, if it were not for the low level officers and non-com on the beach, it would have fail if they waited for orders. Give credit to those guys on the beach that took the initiative to work towards their individual objectives. They were the ones that led the attack!

The plans for the Overlord Invasion, (Normandy) began long before Ike was involved. Actually they were begun by British General Morgan. Ike was the Supreme Commander, however british F.M Momtgomery was in command of all forces during the initial invasion. You are certainly correct regarding who the credit for the successful assault were. The common everyday man who landed or served on board ship during that invasion. American, Canadian, British, etc. Airborne, Infantry, Armoured or Sailor. They are the people who made the invasion work!

On D day June 6th 1944. Code name operation Overlord,
General Montgomery (British) was Land commander, he also adjusted the plans for Overlord to increase the first wave to 150,000 men as opposed to 90,000. In September Eisenhower the supreme allied commander also took over the role of Land commander. The duals roles Eisenhower took on were most likely a political decision. It was election year in the USA. The politicians believed the American people would not accept a "Limey" general running US armies. Irrespective that this Limey General had already controlled armies in the field and defeated the Germans twice in battle. Eisenhower was still awaiting his first Successful encounter with the enemy. Eisenhower adopted the broad front approach to battle where as Montgomery and Patton (general USA)advocated the smaller concentrated approach.