First recorded by Johnny Janis (1960).
Hit version by Johnny Mathis (US #6/MOR #2 1962).
From the wiki: “Paul Vance and Leon Carr wrote ‘Gina’ in 1960 and it was first recorded that same year by singer-guitarist Johnny Janis specifically for an episode (titled ‘Gina’) of the CBS TV series Diagnosis: Unknown in which Janis had a small role. In 1962, a cover recording by Johnny Mathis became Mathis’ highest-charting song since 1957’s ‘Chances Are’.”
Johnny Mathis, “Gina” (1962):