Vinton began writing the song while serving in the Army. The song describes a soldier who is sent overseas and has no communication with his home. The singer laments his condition and wishes for someone to talk with. The single of Vinton's recording was released just as the Vietnam War was escalating and many soldiers were experiencing a similar situation. Vinton's version was noted for his sobbing emotionally during the second verse. Vinton and Gene Allan later re-teamed to compose "Coming Home Soldier", which reached No. 11 on the Billboard Hot 100 in January 1967.

Epic Records never had much initial faith in Bobby Vinton, but he turned out to be their best selling artist of the 1960s; with this being used as an example of the matter. Bobby included it on his first vocal album "Roses Are Red" (it was done in a single take), but it was not initially released as a single. He wanted the single to be a follow up to his first hit "Roses Are Red" but Epic's executives went with the decidedly similar "Rain Rain Go Away" and then gave "Mr. Lonely" to Buddy Greco, whom they were grooming as their next big superstar. Greco's version reached No. 64 on the Billboard Hot 100 chart on November 10, 1962. When Vinton heard Greco's version on the radio, the executives at the company confessed to him that the move was made because they felt he was not a singer, but rather, a musician and a songwriter. However, in the following months, Bobby's continued success as a vocalist proved them wrong. Many months later, when Epic was preparing a "Greatest Hits" album, they had eleven cuts and asked Bobby what should be the twelfth; "Mr. Lonely" was his response to the question. Following its inclusion, many disc jockeys started to play it - particularly those who remembered Buddy Greco's version and how Epic had shortchanged Bobby on his own song. With this newfound playing came many a demand for "Mr. Lonely" to be released as a single. "Mr. Lonely" became one of Bobby's signature songs and a favorite with servicemen around the world. Epic subsequently built an entire album release around "Mr. Lonely" when it became a hit as a single.

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