Definitions of Distinguished Conduct Medal. The reverse on all issues bears the inscription " FOR DISTINGUISHED CONDUCT IN THE FIELD". The Distinguished Conduct Medal, post- nominal letters DCM, was established in 1854 by Queen Victoria as a decoration for gallantry in the field by other ranks of the British Army. The original obverse of this medal depicted a trophy of arms as seen on early Army Long Service and Good Conduct Medals. The Complete New Zealand Distinguished Conduct Medal.