An animator is an artist who creates images, known as frames, which give an illusion of movement called animation when displayed in rapid sequence. Animators can work in a variety of fields including film, television, and video games. Animation is closely related to filmmaking and like filmmaking is extremely labor-intensive, which means that most significant works require the collaboration of several animators. The methods of creating the images or frames for an animation piece depend on the animators' artistic styles and their field.

Other artists who contribute to animated cartoons, but who are not animators, include layout artists (who design the backgrounds, lighting, and camera angles), storyboard artists (who draw panels of the action from the script), and background artists (who paint the "scenery"). Animated films share some film crew positions with regular live action films, such as director, producer, sound engineer, and editor, but differ radically in that for most of the history of animation, they did not need most of the crew positions seen on a physical set.

In hand-drawn Japanese animation productions, such as in Hayao Miyazaki's films, the key animator handles both layout and key animation. Some animators in Japan such as Mitsuo Iso take full responsibility for their scenes, making them become more than just the key animator.

Animators often specialize. One important distinction is between character animators (artists who specialize in character movement, dialogue, acting, etc.) and special effects animators (who animate anything that is not a character; most commonly vehicles, machinery, and natural phenomena such as rain, snow, and water).

Stop motion animators do not draw their images, instead they move models or cut-outs frame-by-frame, famous animators of this genre being Ray Harryhausen and Nick Park.

In large-scale productions by major studios, each animator usually has one or more assistants, "inbetweeners" and "clean-up artists", who make drawings between the "key poses" drawn by the animator, and also re-draw any sketches that are too roughly made to be used as such. The terms "assistant animator" and "clean-up artists" tend to be used in place of each other. Usually, a young artist seeking to break into animation is hired for the first time in one of these categories, and can later advance to the rank of full animator (usually after working on several productions).

Historically, the creation of animation was a long and arduous process. Each frame of a given scene was hand-drawn, then transposed onto celluloid, where it would be traced and painted. These finished "cels" were then placed together in sequence over painted backgrounds and filmed, one frame at a time.

Animation methods have become far more varied in recent years. Today's cartoons could be created using any number of methods, mostly using computers to make the animation process cheaper and faster. These more efficient animation procedures have made the animator's job less tedious and more creative.