No one! He wasn’t made. He has always existed. Only something that has a beginning needs a beginner or a maker. The First Cause or Cosmological argument goes like this…  

1. Whatever begins to exist (an effect) needs a cause. Something cannot begin to exist from nothing.
2. The universe (the effect) began to exist ( at the so-called Big Bang, the creation of the universe).
3. Therefore, the universe (the effect) has a cause.

     Please note that we are not saying that everything needs a cause. We are saying that everything that begins needs a cause for it to exist. The universe is a good example. All scientists agree that the universe had a beginning. Therefore, the universe needs a cause.      

     Now we can ask, “Who caused the universe?” An important thing to note is that you cannot keep going back by asking “Who caused that cause?” and then “Who caused that cause?”.
This ‘keep going back’ question is known as an infinite regression. Infinite regressions are possible in theory but not in real life. An infinite regression of finite causes doesn’t answer the question of ‘source’, it merely makes the ‘effects’ more numerous.

Eventually you must get to what philosophers call the ‘First Uncaused Cause’. This cause was not started by something else. This Cause is self-existent. It has always existed. Another word for this First Uncaused Cause is God.

When you ask the question, “Who made God?”, its like asking “Who is the bachelor’s wife?” By definition, a bachelor doesn’t have a wife, so asking who is the bachelor’s wife is non-sensical. By definition, God is not made. Nobody made Him. He is the first uncaused cause.

For an excellent short video, go to The Cosmological Argument video

Also see How could God have always existed?

Book reference:
“Who Made God?” by Zacharias & Geisler, page 23
“That’s Just Your Interpretation” by Dr. Paul Copen, page 69
“I Don’t Have Enough Faith to be an Atheist” by Geisler & Turek, chapter 3

Website references:

For His Kingdom,
Dave Maynard