Rai was commissioned into Bombay Sappers on 15 December 1976. He is a third generation officer in the army and has vast operational and command experience. He has commanded an armored engineer Regiment; a mountain brigade in the North East India; a Counter Insurgency Force in Jammu and Kashmir; XII Corps (Jodhpur); Chief of Staff South Western Command and GOC-in-C Eastern Command. He has also held various staff appointments including Directing Staff at Defence Service Staff College; Colonel General Staff Operations of a high altitude Corps; Chief Engineer of a Desert Corps; Brigadier General Staff at Army Training Command and Deputy Director General at Military Operations Directorate (Army HQ). He was also the Colonel Commandant of the Bombay Sappers.[1][2][6][7]