In the anime, Garp said he has eaten 842 donuts without sleeping or taking a break because he was trying to beat a world record.
Aside from Luffy himself, Garp is the only Romance Dawn V.2 character to actually appear in the storyline.
Garp’s laughter style is that he adds either “Bwa” or “Wa” before the haha part. This is somewhat unique as most characters only stick with one laughter style (the other being Dracule Mihawk).
Garp appears to have a dog animal-theme, as shown by his mask and his ship.
In an SBS question on Volume 59, a fan pointed out the fact that despite Garp’s few appearances, his trademark scar has disappeared 25 times if counted up to Volume 58. In response to the statement above, Oda responded by saying that “if an enemy he hates is around, his scar tingles, and it will float up”. He speaks of how Garp’s “true form” may be the scar-less one, but he also points out that this is not proved anywhere. This is obviously a joke answer, as Oda is fond of them.
As a kid, Garp had a very similar appearance to Luffy and Ace, despite not being blood-related to the latter.
Due to his grudge against him, Chinjao wants Garp to suffer the pain of losing someone close to him. Ironically, Garp already underwent that pain upon losing Ace.
In the 5th fan poll, Garp ranked 74th.