Jaeger joined the West Nova Scotia Regiment (Reservist Unit) in 1976, while attending Acadia University.
During this appointment Jaeger "had the privilege of leading the unit in support of the 1997 Manitoba flood and the 1998 Ice Storm.
"[5] That same year, Jaeger took on a six-month instructing position at Canadian Land Forces Command and Staff College, also known as "Foxhole U".
Jaeger was promoted to Colonel in 2000, and "posted to Ottawa where [she] served as director of Health Services Operations and medical advisor to the chief of land staff and the surgeon general.
In 2009 she was "deployed to the International Security Assistance Force (ISAF) HQ in Kabul overseeing medical support to NATO’s mission in Afghanistan.