Tyler Armstrong of Yorba Linda climbed the 22,000-foot peak, the highest in the Americas, with his father, KNBC, Los Angeles, reported.
Tyler's trek is aimed at raising awareness of and money for research into Duchenne muscular dystrophy, which only afflicts boys.
"It's when muscles get smaller every time you use them and by 14 they can't walk," he said.
Tyler was an experienced climber when he set out to climb Aconcagua. At 7, he reached the summit of Mount Whitney in California, the highest peak in the Lower 48.
Last year, he took on Mount Kilimanjaro in Tanzania, which is both Africa's highest mountain and the tallest free-standing peak on the planet. He had to get a special permit because he was a year under the minimum age for the climb.