As difficult as it might be to fathom today — when the man known to all the world as "Jack" has journeyed from respected actor to movie star to superstar to pop-culture touchstone — as hard as it might be to grasp, there was a time when John Joseph Nicholson was merely another Hollywood up and comer. More promising and talented than many, perhaps. Certainly more riveting, as both an artist and as an individual, than most. But still, in the late 1960s, Jack Nicholson was just Jack Nicholson: a guy with some interesting, supporting roles under his belt and, one suspected, a slew of starring roles in his future.
In September 1969, not long after Nicholson had charmed moviegoers and critics alike with his deceptively easygoing performance as a sweet-natured, booze-sodden, small-town lawyer in Dennis Hopper's Easy Rider, LIFE sent Arthur Schatz to photograph the 32-year-old actor at his new home on Mulholland Drive, overlooking Franklin Canyon in Los Angeles. Here, LIFE.com offers a series of Schatz's photographs from that shoot that were never published in LIFE.
In pictures that feature Nicholson playing with his 5-year-old daughter, Jennifer; taking his very first piano lesson from teacher Josef Pacholczyk in preparation for his next role (as classical pianist-turned-roughneck Robert Dupea in one of the great American films of the 1970s, Five Easy Pieces); hanging out with his friend and the director of Five Easy Pieces, Bob Rafelson; and generally enjoying the good life in sunny California, Schatz captured the private side of a man on the brink of what would prove to be life-changing stardom.
In typed notes by writer Judy Fayard that accompanied Schatz's film to the LIFE offices New York, meanwhile, one discovers small insights into the man who, one day, would be acknowledged as Hollywood's uncrowned king. For example, Fayard recalls that at one point during the shoot, Nicholson — who in 1969 drove a yellow convertible VW bug — stated that "anyone out here who doesn't drive a Volks is either ostentatious or stupid."
(Of course, reading that quote in 2012, it's hard not to ask the question: What does Jack drive these days?)
Ultimately, though, perhaps the most fascinating aspect of these pictures, four long decades later, is how recognizable today's Nicholson is in them — that is to say, how recognizably Jack he is in them. The energy, the charisma, the intelligence, the well-known (and so-often lovingly parodied) grin: these are all utterly familiar traits of a singular figure who, well into his 70s, continues to command not only the big screen, but any public event — the Oscars, a Lakers game, a golf tournament — he happens to attend.
More than any other actor alive, Jack happily looms like some trickster colossus over the entire Hollywood landscape . . . and no one anywhere begrudges him his dominion.