Early origins of the Beau family surname revolve around Nicolas LeBeau in the early 1300s, a famous knight and lord in Southern France.
The name Beau used as a given name was first recorded in England and Wales in 1910. Previously, it was traditionally used in the long-form as Beaumont or Beauchamp throughout the 18th century and into the 19th century.
As a surname, Beau is found in the USA, UK, Canada, and Scotland between 1840 and 1920. Beau is also found in Germany as Lebeau (source).
The oldest recorded birth by the U.S. Social Security Administration for the first name Beau is Wednesday, February 12th, 1873 (source).