When Charlie Porter showed up in the Yosemite Valley in the early 1970s and started forging new climbing routes up the famously imposing monolithic rock wall known as El Capitan, he was something of a mystery man, a stranger to the clubby group of mostly Californians who had made Yosemite the center of the climbing world.

He was from the East somewhere — Massachusetts, it turned out — and he had not grown up in the sport the way just about every other accomplished climber had, but his skills seemed otherworldly.

In 1972, he and another climber, Gary Bocarde, established the Shield, which became perhaps the most famous route up El Capitan. That same year, he made the first recorded ascent of the overhanging southeast face of the El Capitan wall, doing it solo, and named the route the Zodiac. In 1973, he scaled the southeast face again by a different route with different challenges, calling it Tangerine Trip, and by the summer of 1974 had established two other paths, Mescalito and Grape Race.

These were world-class feats of mountaineering, but if Mr. Porter, who died at 63 on Feb. 23 in Punta Arenas, Chile, was a mystery then, in many ways he remained one.