On August 15, 2012, Hernandez threw the 23rd perfect game in Major League Baseball history against the Tampa Bay Rays in a 1–0 victory at Safeco Field. It was also the first perfect game in Seattle Mariners franchise history. His perfect game remains the most recent in Major League Baseball.

On April 23, 2016, he claimed the record for most strikeouts by a Mariners pitcher when he struck out Rafael Ortega of the Los Angeles Angels for his 2,163rd strikeout as a Mariner pitcher. The previous record of 2,162 strikeouts had been held by Randy Johnson. His 146th win, which occurred on May 9, gave him the club record in that category as well, surpassing Jamie Moyer.

This Rawlings official MLB baseball was signed in blue by Hernandez and includes a JSA sticker and COA. There is some smudging to the signature as seen in photos.