c.1534, "a running course" (especially of the sun, etc., across the sky), from M.Fr. carriere
"road, racecourse," from O.Prov. carriera,
from V.L. *(via) cararia
"carriage (road), track for wheeled vehicles," from L. carrus
"chariot" (see car
). Sense of "course of a working life" first attested 1803. The verb is first attested in 1594 from the notion of a horse "passing a career" on the jousting field, etc. Careerist
is from 1917.