He signed the letter: "Love and kisses, Your son Johnny. I'll be seeing you soon, I hope."
Gonsalves died in 2015. His mother has died as well. But the USPS found an address for his widow, Angelina, whom the soldier met five years after he sent the letter.
Alongside the decades-old mail, USPS employees also sent a letter of their own, saying "delivering this letter was of utmost importance to us".
After the Gonsalves family received the letter, they called the facility and thanked them.
"Imagine that! Seventy-six years!" Angelina Gonsalves told WFXT-TV. "I just couldn't believe it. And then just his handwriting and everything. It was just so amazing."
Angelina Gonsalves, 89, spent another holiday without her husband, but she said this year "it's like he came back to me, you know?"