Major-General Petras was born in Austria and raised in Sudbury, Ontario. He has a Bachelor of Arts Degree from Laurentian University, in Sudbury, and a Masters Degree from the University of Toronto.
His civilian career was in the education sector, where he served as Director of Athletics, and then Principal of St Charles College. While holding the appointment of Director General Land Reserve, he worked in a half time capacity as a senior administrator at the Sudbury Catholic School Board.
Major-General Petras began his military career at the age of 16 when he joined 33 Technical Squadron Royal Canadian Electrical and Mechanical Engineers. He attained the rank of Warrant Officer. On graduation from university he transferred to the infantry and was commissioned as a Lieutenant. He held various regimental appointments, including operations officer and company commander. During the summer of 1976, he qualified as a military parachutist, followed by Staff College. He was appointed Deputy Commanding Officer of the Second Battalion the Irish Regiment of Canada in September of that year.
In 1979, he was promoted to Lieutenant Colonel and appointed as Commanding Officer to the Second Battalion. In 1980, he was selected to attend the United States Marine Corps Command and Staff College in Quantico, Virginia, USA. In October of 1982, following presentation of Colours to the unit, he relinquished command of the 2nd Battalion and was subsequently appointed Deputy Commander of Northern Ontario Militia District (now 33 Canadian Brigade Group). He was appointed Commander in 1985. On relinquishing command in 1988, General Petras was posted to Land Force Central Area Headquarters (Strategic plans). In 1991 he was appointed Director of the Militia Officer Training School and in 1994, Deputy Chief of Staff (Operations) at Land Force Central Area Headquarters.
He was promoted to the rank of Brigadier-General and appointed Deputy Commander of Land Force Central Area in 1996. In August 1999, he was posted to Chief of Land Staff, to do Language and Senior Leadership training. The following year, Major-General Petras was appointed Director General Land Reserves in Land Staff. In July 2003, he was appointed Director General Land Combat Development in Kingston, Ontario, serving in a full time capacity until his appointment as Chief - Reserves and Cadets in December of 2004.
He was appointed Commander in the Order of Military Merit in 2006.
