His feats in the United States, India and Nepal have a large following and fans have viewed pictures of his New Zealand trip posted on social media.
Mr Kumar applied for residency in New Zealand even before setting foot in the country, and hitch-hiked to Cape Reinga on the day he arrived to begin his journey.
In addition to a small injury in the South Island, he had a "near-death experience" on his travels.
In September, while tracking through an ancient Northland kauri forest, he was swept away by flood-swollen waters in the Waipapa River.
"I wrote in my journal, 'Mum, Dad, I'm sorry, I love you,' and put it in my waterproof pocket in case I did not survive the crossing."
Mr Kumar said he had been granted New Zealand residency and was looking for a job, and more long-distance adventures.
He is "chief experience officer" for the Bedrock Sandals company in California and is accompanied on this trip by the company's co-founder, Dan Opalacz. As a poor youth, Mr Kumar enviously watched hordes of passing backpacker tourists in the city of Chennai in southern India.
His own chance to become an adventurer followed when he took up a scholarship to Madras University, and was recruited to Silicon Valley's big software firms as an engineer.
While on Te Araroa for 85 days, he has been raising money for Tear Funds, a New Zealand charity against human trafficking.
He hopes to do more for charity in his next endurance feat: the Cook to Cook Challenge, in which he will climb Aoraki Mt Cook and run from there to Picton, instead of cycling it like other competitors.
