The yellowtail rockfish was first formally described as Sebastodes flavidus in 1862 by the American ichthyologist William Orville Ayres with the type locality given as San Francisco, California.

The specific name flavidus means "yellowish", thought to be a reference to the "yellowish green" colour on the flanks, which Ayres said easily differentiates this species "as they lie in heaps upon the fish-stalls" from the "closely allied" black rockfish (S. melanops) Some authorities suggest that the name refers to the "bright yellow tail", but the tail was not described by Ayres.

The body darkens and becomes uniformly olive green and the blotches fade following capture although some reddish-brown speckling is often still present on the rear margin of each scale.

[5] The yellowtail rockfish occurs from San Quintin, Baja California,[4] to Kodiak Island, Alaska.

A unique feature of this species is that it can release gas from its swimbladder and this means that when they are caught from deep they are able to avoid barotrauma that would be fatal to other fishes.