Diminutive or variant of Marlon, possibly from a French surname, or associated with the marlin fish.
Marlin moves through cultural space on two very different currents. As a name, it most likely derives from the Old French Merlin — itself traceable to the Welsh Myrddin, a name associated with the great wizard of Arthurian legend whose counsel guided King Arthur through the founding of Camelot. The etymology of Myrddin is debated, possibly linking to a place name or to the Welsh word for sea-fort, but the mystical associations of Merlin have given any derivative form a subtle aura of wisdom and enchantment.
The name also connects to the natural world through the Atlantic marlin — a powerful, sleek, deep-ocean fish celebrated for its speed and fighting spirit. Ernest Hemingway's The Old Man and the Sea, while not featuring the name itself, embedded the marlin permanently into the mythology of struggle, endurance, and the individual's contest with nature. This aquatic resonance gives Marlin an adventurous, outdoorsy quality that feels especially American.
In popular consciousness, the name received a significant contemporary boost through Pixar's 2003 film Finding Nemo, in which the anxious but devoted clownfish father Marlin swims thousands of miles of open ocean to rescue his son. That portrayal — loving, determined, ultimately courageous — gave the name a warm paternal association for an entire generation. Marlin sits comfortably in the tradition of names that feel both rooted and a little rare: recognizable without being common, touched equally by Arthurian legend, the open sea, and one of cinema's most beloved animated fathers.