Implied volatility surfaces of individual equity options exhibit persistent volatility, pronounced skew, and upward-sloping term structures. These features correlate with market index patterns, but also reflect stock-specific sources of return variation. We develop an affine jump-diffusion model that decomposes returns into systematic and idiosyncratic diffusive and jump components, incorporating leverage effects, asymmetric jumps, and a time-varying jump intensity. Estimated on 50 large-cap U.S. stocks from 2006-2021, the model closely matches the dynamics of implied volatility and yields substantially lower pricing errors than nested alternatives. It offers novel insights into the risk-neutral dynamics of equity return variation.