Having been at Sotheby's since 1979, he became head of their English furniture department in 2000.
The last sale he undertook for Sotheby's on December 7 included the Harrington marquetry commode sold for a record £3.35m.
Bonhams CEO Matthew Girling said: "Fergus will be a great asset to Bonhams as we seek to be the number one player in the furniture market."
