His mother actively pursued arts and crafts as a pastime, his father enjoys photography, his brother Matt is a musician, and his older brother Dave, like Giarrusso himself, enjoys drawing.

Giarrusso looked up to Dave in particular, and names him as the primary creative influence on his art style and career.

He was also influenced by the newspaper strips he and his brother read, most notably Charles Schultz's Peanuts.

Others included Garfield, B.C., For Better or For Worse, Heathcliff, Marmaduke, Dennis the Menace and Beetle Bailey.

[3] Giarrusso is also known for writing and illustrating G-Man, an all-ages series by Image Comics featuring a young superhero who gains the powers of super strength, super endurance, and flight when he wears a magic cape.