Dias enlisted in the army after completing his schooling on 11 August 1980 undergoing officer training at the Sri Lanka Military Academy at Diyatalawa; and commissioned to the 1 Vijayabahu Infantry Regiment as a Second Lieutenant on 27 February 1982. Afterwards he received an Inter Regimental transfer to Gajaba Regiment and went on to serve as the Commanding Officer of the 10th Gajaba Battalion and later served the Officiating Commandant at the Regimental Headquarters of the Gajaba Regiment. He was promoted to the ranks of captain in 1986, major in 1994, lieutenant colonel in 1995 and had undertaken the Young Officers' Course, Senior Command Course, MCC Course, CIMIC Course and the Senior Crisis Management Seminar.
In 2000 he was promoted to colonel and was appointed Officiating Commander of Special Forces Brigade and Officiating Commander, 516 Brigade till 2001. In 2001 he was appointed Officiating Inspector Infantry, Army Headquarters till 2003. He was promoted to brigadier in 2005 and major general on 18 February 2008.
During his military career he held many appointments. The include; Adjutant General (2012–2014), Deputy Chief of Mission to the Sri Lanka Embassy in Berlin (2009–2011), General Officer Commanding 57 Division (2007–2009), General Officer Commanding 56 Division (2006–2007), Commander 233 Brigade (2005–2006), Commandant, Infantry Training Centre, Officiating Commander for 534 Brigade (2003–2004), Officiating Inspector Infantry, Army Headquarters (2001–2003), Officiating Commander, 516 Brigade (2000–2001), Coordinating Officer Ariyalai, Officiating Commander, 551 Brigade, Commander 553 Brigade, Officiating Colonel GS, Directorate of Operations, Army Headquarters, Officiating Commandant Gajaba Regiment Regimental Headquarters, Commanding Officer, 10 Gajaba Regiment and many other appointments.
Foreign assignments reported by the military include: Pakistan,
Qatar, Oman, US, India, Czech Republic, Turkey, China, Russian Federation,
Australia, Germany & South Korea.
If a nation forgets its past it is certainly not focused to face the future
Jagath Dias
Year
Position Held
2000
Officiating Commander of Special Forces Brigade
2000-2001
Officiating Commander, 516 Brigade
2001-2003
Officiating Inspector Infantry, Army Headquarters
2003-2004
Commandant, Infantry Training Center, Officiating Commander, 534 Brigade
2005-2006
Commander 233 Brigade (note: this is during the final war in the East)
2006-2007
General Officer Commanding 56 Division
2007 Feb
57 Division created (consisting of 571, 572, 573 Brigades and then in October 2008 the 574 Brigade was added)
2007-2009
Appointed General Officer Commanding 57 Division
2009-2011
Deputy Chief of Mission to the Sri Lanka Embassy in Berlin (Also accredited to Switzerland and the Vatican)
2012–2014
Adjutant General for the Sri Lankan Army
2014 Jan
Security Force Commander Mullaitivu
2015-2016
46th Chief of Staff of the Army
General Jagath Dias led the 57 Division; he did a tremendous task because it was his responsibility to regain Kilinochchi. He was there from the very beginning of the Humanitarian Operations till the very last minute.
Sri Lanka
Sri Lanka Army
Major General
Weera Wickrama Vibhushanaya
Rana Wickrama Padakkama
Rana Sura Padakkama
Uttama Seva Padakkama