Who decided to get rid of prayer in public schools?

Answer 1

Thomas Jefferson.

Believing with you that religion is a matter which lies solely between Man & his God, that he owes account to none other for his faith or his worship, that the legitimate powers of government reach actions only, & not opinions, I contemplate with sovereign reverence that act of the whole American people which declared that their legislature should "make no law respecting an establishment of religion, or prohibiting the free exercise thereof," thus building a wall of separation between Church & State.

- Letter to Danbury Baptists

This separation was seen as ideal for all involved, as churches did not want government to interfere in religious affairs, which had been common in Europe.

America's mixture of various religions, and many with no religion at all, lends itself well to this religious neutrality in public schools. Many are also free to attend private religious schools, be home-schooled, or have supplemental teaching of religion by their respective church. Students also have the full freedom to pray in public schools, but this activity is not led or sanctioned by the school or its officials. So, for example, a student is free to say grace prior to eating lunch, or to pray undisruptively before a big test.