Stewie ranks at #653 with 187 entries, registered male. The name is most strongly anchored on American pet registries by Stewie the football-headed baby from Family Guy, and a meaningful share of registry Stewies live in households where the show has been part of the cultural diet since the early 2000s.
The Family Guy effect
Stewie Griffin (Family Guy, Fox, 1999 onward) is one of the most recognizable cartoon characters in 21st-century American animation, and the character's combination of British-accented eloquence and toddler-misanthropy reads cleanly onto a small confident dog with attitude. The naming wave from this overlay is the single largest cultural anchor on pet Stewie, and most owners would name the show as the source if asked.
The diminutive-of-Stewart layer
For a smaller cohort, Stewie functions as a friendly diminutive of Stewart or Stuart, with no cartoon reference. These are usually older owners who picked the name well before Family Guy's cultural reach landed, or households where the name carries a family-naming connection (a relative or grandparent named Stuart). The two reading paths converge on the same registered name.
Sound and breed lean
Two syllables, front-stressed (STOO-ee), with a soft sibilant opening and clean recall. The shape works well in noisy environments. The name lands disproportionately on small expressive breeds where the Stewie-character register clicks: Chihuahuas, Jack Russells, Pomeranians, and small attitude-forward mixed-breeds. The human Stewie page shows minimal SSA presence; pet Stewie owns the cultural space.