Earlier this month, the 26-year-old athlete covered more than 30 treacherous kilometers from Zermatt to Saas Fee, Switzerland, on foot.
On the way, he crossed five 4,000-meter peaks including the Dom, the highest mountain in Switzerland, in just seven and three-quarter hours.
The mountains and their challenges have always been part of life for Steindl, who grew up in Zermatt as the son of a mountain guide father and an amateur mountaineer mother.
As a 14-year-old, he achieved his first 4,000m ascent on the Matterhorn, and he now holds the record for its quickest ascent from Zermatt -- fractionally under three hours.
Now a mountain guide himself, he set his five-peak challenge "because I always see the Taeschhorn and the Dom from my home, two beautiful pyramids that glow in the evening sun."
"I was eager to climb them, but the descent from the Dom is quite tricky," he explains.
"I wanted to find a safe way down to the valley, since I'm on my own out there. That's why I chose the route across the five peaks -- Alphubel, Taeschhorn, Dom, Lenzspitze and Nadelhorn."
He first ran the route in 2013, but has had to wait patiently for a chance to repeat the feat.
The Swiss climber needed perfect weather conditions in which exposed ridges were free of snow, and the firn -- crystalline or granular snow -- was frozen.
And two years -- yes, two years -- later, that perfect day finally arrived.
Steindl's remarkable challenge was captured by a film crew, and he says he hopes the results "can inspire people at home and encourage them to go out and explore the mountains."
After six hours and 37 minutes, during which the camera crew often had difficulty keeping track of him amid vast expanses of landscape, he stood atop Nadelhorn.
And a little over an hour later, exhausted but ecstatic, he arrived in the church square in Saas Fee.
"I just wanted to do my best, but I never expected to achieve such a time," he adds. "I thought my watch must be faulty.
"It was an amazing day for me -- I am tired but satisfied and happy. You cannot top such a perfect day in the mountains, and now it has been captured it forever."