A different word used to refer to an old soldier is veteran. A veteran is someone who served our country in the past.
Another word for not old is young.
Another word for 40 year old is 4 decades. 8D
Another word for an old female cat is a grimalkin.
Ancient.
Another word for an old friend is longtime acquaintance. Others include bosom buddy, pal, homie, confidant, ally, and lifelong friend.
You could use "Once a doctor and a soldier, ...." or "Previously a doctor and a soldier, ...."
If a soldier is absent long enough he will be declared a deserter.
Miles (genitive: militis).
Dough boy was a soldier in II world warDog face was a soldier in the I world war
One word would be mercenary.
soldier
Another word for not old is young.
Troop is an old-fashioned word for soldier, from trooper.
"Ancient" is another word for very old.
NIGGAHS
The Middle French word "pioneer" which comes from the Old French word "paonier" which means "foot soldier"
Policeman, fireman, soldier, sailor, airman, marine, etc.