The name Costello is a boy's name of Irish origin meaning "from England". Costello and is often added to lists like Irish Names for Dogs and discussed in our forums with posts like "Adding then Eliminating - Boys Themed".
From the experts:
The fashion for using surnames as firsts has extended beyond the familiar Morgan and Parker to more ethnic-sounding choices such as Cohen and O'Brien to -- why not? -- this quintessentially Irish name with the friendly o ending.