The name Kayleb is a modern variation of the Hebrew name Caleb, which is derived from the biblical figure Caleb from the Old Testament. The name Caleb is believed to have originated from the Hebrew word "kelev," meaning "dog" or "faithful companion."

In the Book of Numbers, Caleb is introduced as one of the twelve spies sent by Moses to explore the land of Canaan. Caleb and Joshua were the only two spies who remained faithful to God and encouraged the Israelites to proceed with the conquest of Canaan. As a result, Caleb was rewarded with a portion of land in the Promised Land.

The earliest recorded use of the name Caleb can be traced back to the biblical account, making it one of the oldest names in recorded history. Throughout the centuries, the name has been used across various cultures and regions, often associated with its biblical origins and the virtues of faithfulness and loyalty.

One of the earliest notable figures with the name Caleb was Caleb Cushing, an American lawyer, politician, and diplomat who served as the United States Attorney General from 1853 to 1857. Another prominent individual was Caleb Brewster, a American Revolutionary War spy who played a crucial role in the Culper Ring, a spy network that provided valuable intelligence to the Continental Army during the war.

In more recent history, Caleb Carr, an American novelist and military historian born in 1955, is known for his bestselling novel "The Alienist." Caleb Followill, born in 1982, is the lead singer and guitarist of the American rock band Kings of Leon.

The name Kayleb, while a modern variation, carries the essence of the original Hebrew name Caleb. It has gained popularity in recent years as a unique and distinctive name choice, often associated with its biblical roots and the virtues of faithfulness and loyalty.