1810, "art of a general," from French stratégie (18c.) and directly from Greek strategia "office or command of a general," from strategos "general, commander of an army," also the title of various civil officials and magistrates, from stratos "multitude, army, expedition, encamped army," literally "that which is spread out" (from PIE root *stere- "to spread") + agos "leader," from agein "to lead" (from PIE root *ag- "to drive, draw out or forth, move"). In non-military use from 1887.
<a href="https://www.etymonline.com/word/strategist">Etymology of strategist by etymonline</a>
Harper, D. (n.d.). Etymology of strategist. Online Etymology Dictionary. Retrieved $(datetime), from https://www.etymonline.com/word/strategist