A Wikipedia definition…

A puppeteer…
is a person who manipulates an inanimate object—a puppet—in real time to create the illusion of life. The puppeteer may be visible to or hidden from the audience. A puppeteer can operate a puppet indirectly by the use of strings, rods, wires, electronics or directly by his or her own hands placed inside the puppet or holding it externally. Some puppet styles require puppeteers to work together as a team to create a single puppet character.
There are a wide range of styles of puppetry but whatever the style, the puppeteer’s role is to manipulate the physical object in such a manner that the audience believes the object is imbued with life.