 John de Havilland began his career as an officer of arms in 1866 when he was appointed Rouge Croix Pursuivant of Arms in Ordinary.On 26 March 1872, he was promoted to the position of York Herald of Arms in Ordinary.It is also notable that de Havilland helped in the publication of the 1878 edition of "Burke's General Armory", which remains a standard reference work for those interested in heraldry.