Shadrach appears to be derived from the Akkadian Shadar, command of, and Sumerian, Ark, the moon-god. However, it was more likely a corruption of Marduk, the city-god of Babylon as well as the Babylonian name give to Hananiah, the chief of the three Hebrew children.
He was a Hebrew youth taken captive around 605 BCE. Being found of good character and intelligent he was placed along with three other Hebrew youths in the college of magicians of the Chaldeans after being tutored in their language and learning.
Like Daniel, he lived on leguminous plants such as peas and beans, and water. He, along with his companions, were found superior over all other magicians and finally stood before King Nebuchadnezzar (Dan. 1:7).
The king was unable to recall a dream or vision, when the magicians were unable to assist him he threatened to slaughter them all. Shadrach encouraged them, and with God’s help Daniel was able to recall the king’s dream and interpret it, thus being promoted to high civil office.
Shadrach along with Meshach and Abednego by their determination and faithfulness converted the king and country to the worship of Jehovah.
Due to their notoriety some envious Chaldeans promoted a decree signed by the king that the subjects were to worship a golden image at a certain place designated the Dura. The three refused, and for their refusal were placed into a fiery furnace. Miraculously their faith saved them from extinction. Upon witnessing this, the king accepted Jehovah as God. A.G.H.
Unger, Merrill F., Unger’s Bible Dictionary, Chicago, Moody Press, 1966, p. 1001