Born in Nagano, Japan, Kobayashi set his first record at his rookie appearance on July 4, 2001, when he ate 50 hot dogs in 12 minutes at the Nathan's Coney Island Hot Dog Eating Contest, doubling the previous record of 25.
Lahir di Nagano, Jepang, Kobayashi meraih rekor pertamanya dalam penampilan pertamanya pada 4 Juli 2001, ketika ia memakan 50 hot dog dalam 12 menit di kontes memakan hot dog Nathan's di Pulau Coney, mengalahkan rekor sebelumnya yang berjumlah 25.