The name Kayli is believed to have originated from the Old English language, where it was derived from the Germanic word "kal," meaning "bald" or "bold." This name likely emerged in the early medieval period, around the 5th to 8th centuries, when Anglo-Saxon culture flourished in parts of what is now England and northern Germany.

One of the earliest recorded instances of the name Kayli can be found in the Domesday Book, a comprehensive survey of landholdings and population in England commissioned by William the Conqueror in 1086. In this document, there is a record of a landowner named Kayli, who held estates in the county of Gloucestershire.

During the Middle Ages, the name Kayli appeared occasionally in various chronicles and records, although it was not as common as some other names of the time. One notable bearer of the name was Kayli de Montfort, a 13th-century English noblewoman who was a member of the prominent Montfort family and played a role in the Barons' War against King Henry III.

In the 16th century, a Kayli Cromwell was recorded as a member of the household of Thomas Cromwell, the influential adviser to King Henry VIII. This Kayli Cromwell may have been a distant relative of the famous Oliver Cromwell, who later became Lord Protector of England in the 17th century.

Another historical figure who bore the name Kayli was Kayli Raleigh, a 17th-century English explorer and colonist who accompanied Sir Walter Raleigh on expeditions to the Americas. Kayli Raleigh is credited with helping to establish the first English settlement on the island of Roanoke, off the coast of present-day North Carolina.

Moving into the 18th century, a Kayli Austen was recorded as a distant cousin of the renowned novelist Jane Austen. While little is known about Kayli Austen's life, her existence suggests that the name Kayli continued to be used, albeit in a limited capacity, among certain English families during this period.