Sir Alex Ferguson snapped up the hard-working frontman in 2010 and helped a prolific presence to become a firm fan favourite at United.
Hernandez admits that a productive spell in Manchester saw him living the dream, with the 31-year-old struggling to believe that the Red Devils were interested when Guadalajara were first approached.
He went on to take in 157 appearances for the club, scoring 59 goals, but eventually left for Bayer Leverkusen in 2015 after struggling to secure a regular starting berth.
"[When you join a club like United] it is difficult to find a balance between enjoying it, not getting obsessed over wanting more and thinking that you have already done everything," Chicharito told ESPN.
"It is like bittersweet. It was all amazing and then on the plane I asked myself: And now what?"
Hernandez enhanced his reputation across two years in Germany, earning him another shot at the Premier League with West Ham.
A spell with the Hammers did not play out as planned, with the target found just 17 times, and he remains in the process of trying to rediscover his spark.
MLS side the LA Galaxy acquired him from Sevilla in January, but just two outings were taken in for new employers before competitive football shut down amid the coronavirus pandemic.
Hernandez is determined to prove his worth in America, with there no plans on the part of Mexico's all-time leading goalscorer to head back to Europe any time soon.
He added: "You never know [if I could move back]. I don't know. It's difficult, but why not?
"I'm a person who is assured when I make decisions. I can change my mind, everyone can, but I'm sure of the project that I've chosen [at Galaxy]."
Hernandez is yet to get off the mark for the Galaxy, but does have 156 club goals to his name over the course of his career and a record-setting haul of 52 in 109 appearances for his country.