Traditionally, John the Gospel writer was the disciple whom Jesus loved. However, upon closer study, there is another follower of Jesus that is a stronger candidate that you have likely not considered: Lazarus.
The identity of the “beloved disciple” or the one John calls “disciple whom Jesus loved” is unnamed and has remained a mystery. Irenaeus and Eusebius both identified the beloved disciple as John as early as the second and fourth century respectively. Scholars, such as Raymond Brown, have written heavily upon John as the one whom Jesus loved. Despite the fact John does not self-identify nor names himself as the writer of the Gospel of John or the beloved disciple, we have relied on tradition and church history.
If we are to rely on the tradition of the identification of the beloved disciple, what about the internal evidence of scripture? Surprisingly, scripture does offer dramatic clues to the mystery of the beloved disciple.