Mattel introduced Ken in 1961; since then, he has appeared in many, many versions. Ken has enjoyed a number of careers and has the outfits to prove it. He came in versions with bendable knees, rooted hair, and a dark tan. Some Kens speak Spanish, have jointed trunk sections, or walk lively. In more recent years, Ken's body has become noticeably muscular and defined. The Mod Hair Ken from the mid-1970s is one such variation.