The name Keith has its origins in the ancient Brythonic Celtic languages of Britain. It is derived from the ancient Celtic name Catus, which means "battle" or "warrior". The name Catus was later Latinized to Catutus during the Roman occupation of Britain.

Over time, the name evolved through various spellings like Ket, Chet, and Keit before finally settling on the modern spelling of Keith. The name gained popularity in Scotland during the Middle Ages and was often associated with the powerful Clan Keith, who were known for their military prowess and bravery in battle.

One of the earliest recorded uses of the name Keith can be found in the Scottish Ragman Rolls, a collection of feudal homage papers from the 13th century. In these rolls, a man named Keith is listed as a landowner in the county of Haddington, Scotland.

Throughout history, several notable figures have borne the name Keith. One of the most famous was Sir Robert Keith (1681-1757), a Scottish military officer and governor of Russia. He served as a Field Marshal in the Russian army and was a trusted advisor to the Empress Elizabeth of Russia.

Another prominent Keith was James Francis Edward Keith (1696-1758), a Scottish Jacobite and Prussian military leader. He fought in the Jacobite Risings of 1715 and 1719, and later served as a Field Marshal in the Prussian army under Frederick the Great.

In the 20th century, Keith Holyoake (1904-1983) was a distinguished New Zealand politician who served as the Prime Minister of New Zealand from 1957 to 1960 and again from 1960 to 1972.

One of the most famous Keiths of recent times was Keith Richards (born 1943), the legendary guitarist and co-founder of the Rolling Stones. His contribution to rock music and his iconic guitar riffs have made him a household name worldwide.

Another notable Keith was Keith Jarrett (born 1945), an influential American jazz pianist and composer. He is widely regarded as one of the most important and innovative figures in modern jazz, known for his improvisational skills and emotionally charged performances.