The short answer: Yes. The long answer: It depends on what you mean. If you’re asking whether God’s actions led to Pharaoh going from indifference to outright rejection of God, then yes, that is precisely what happened. If you’re asking whether God acted on Pharaoh’s heart and mind to prevent him from repenting, then no, God did no such thing.

First, let’s take a look at Exodus 5:2. Pharaoh says, “Who is the LORD…I do not know the LORD…” When the story begins, Pharaoh is indifferent to God. He believes in the gods of Egypt and even considers himself a god.

Next, take a closer look at how Pharaoh’s heart is hardened. The phrase is used in three ways:

1) A statement about the future:
“I will harden Pharaoh’s heart.” (Ex. 7:3)

2) Pharaoh hardens his own heart:
“And Pharaoh's heart grew hard, and he did not heed them, as the LORD had said.” (Ex. 7:13)
“Pharaoh's heart is hard; he refuses to let the people go.” (Ex. 7:14)
“Pharaoh's heart grew hard, and he did not heed them, as the LORD had said.” (Ex. 7:22)
“But when Pharaoh saw that there was relief, he hardened his heart and did not heed them, as the LORD had said.” (Ex. 8:15)
“But Pharaoh's heart grew hard, and he did not heed them, just as the LORD had said.” (Ex. 8:19)
“But Pharaoh hardened his heart at this time also.” (Ex. 8:32)
“But the heart of Pharaoh became hard.” (Ex. 9:7)
“And when Pharaoh saw that the rain, the hail, and the thunder had ceased, he sinned yet more; and he hardened his heart, he and his servants. So the heart of Pharaoh was hard; neither would he let the children of Israel go, as the LORD had spoken by Moses.” (Ex. 9:34-35)

3) God hardens Pharaoh’s heart:
“But the LORD hardened the heart of Pharaoh; and he did not heed them, just as the LORD had spoken to Moses.” (Ex. 9:12)
“Go in to Pharaoh; for I have hardened his heart and the hearts of his servants, that I may show these signs of Mine before him.” (Ex. 10:1)
“But the LORD hardened Pharaoh's heart, and he did not let the children of Israel go.” (Ex. 10:20)
“But the LORD hardened Pharaoh's heart, and he would not let them go.” (Ex. 10:27)
“…and the LORD hardened Pharaoh's heart, and he did not let the children of Israel go out of his land.” (Ex. 11:10)

In chapter 5, we see that Pharaoh does not know who God is. He is, therefore, completely indifferent. Contrary to what is often taught, the passage in Exodus 5-12 is not about God’s judgment but about his mercy. There is a good post on this at the Wesleyan Arminian.

According to the speaker at church yesterday, the 10 plagues sent by God attacked Egypt’s gods and proved that he was more powerful than they, one by one. The Nile was a god, the frogs, and even Pharaoh himself, so God sent plagues to show that none of these were truly gods.

Each plague was sent to give Pharaoh an opportunity to repent and let the children of Israel go. That God wished Pharaoh to repent can be seen in Exodus 7:23: “And Pharaoh turned and went into his house. Neither was his heart moved by this.” The ideal outcome was that Pharaoh’s heart would be moved, but it was not.

Pharaoh could have taken these plagues in one of two ways. One, he could do as he did and harden his heart towards God, or two, he could have repented and believed. In fact, in Exodus 9:27 he showed that he knew what it was all about: “And Pharaoh sent and called for Moses and Aaron, and said to them, ‘I have sinned this time. The LORD is righteous, and my people and I are wicked.’” Yet he only desired a reprieve. He was not sincere, and just seven verses later he again hardened his heart.

When God says he will harden Pharaoh’s heart, it means that he is going to send plagues upon Pharaoh. The plagues could have caused either repentence or hardening, but they caused hardening, and God knew they would. This is how God hardened Pharaoh’s heart. When Pharaoh hardens his own heart in Exodus 8:15 it says that he did this “just as the LORD had said,” but remember that God had said that he would harden Pharaoh’s heart. This demonstrates the point precisely.

God’s ultimate objective, i.e. that the Israelites go free, was achieved, despite Pharaoh having free will. If Pharaoh had repented, God’s objective would have been achieved that way, but he did not, so God set them free another way.

This certainly sheds new light on Exodus 33:19 (Romans 9:15): “I will be gracious to whom I will be gracious, and I will have compassion on whom I will have compassion.” Rather than meaning, “I will save whom I choose, and all you losers who weren’t chosen can just suck it up,” it means, “I will show mercy on even the most detestable of men, for I am full of mercy and compassion.” (See God’s words to Pharaoh in Exodus 9:15-16: “Now if I had stretched out My hand and struck you and your people with pestilence, then you would have been cut off from the earth. But indeed for this purpose I have raised you up (spared you), that I may show My power in you, and that My name may be declared in all the earth.”)