Ferb comes from a blended family, a premise the creators considered underused in children's programming and which reflected Marsh's own upbringing. Ferb's birth mother is never revealed, but the series shows that both Ferb and his father Lawrence hail from the United Kingdom. Lawrence married Ferb's stepmother Linda after meeting her at a 1990s concert by the (fictitious) band Love Händel. Marsh considers explaining the family background "not important to the kids' lives. They are a great blended family and that's all we need to know."
Ferb and his family live in the fictional town of Danville, in a large, suburban neighborhood. Throughout their summer vacation, Ferb and Phineas conceive outrageous schemes to defeat boredom while sitting lazily beneath a tree in their backyard. Phineas mainly conceives each project while Ferb spearheads its construction. Their activities are usually beyond the capability of a typical child and have included toy design (in "Toy to the World"); treasure-hunting (in "The Ballad of Badbeard"); engineering (in "It's About Time!"); and restaurant management (in "Chez Platypus"). However, Ferb occasionally reminds his step-sister that they really are just kids. Ferb's stepsister, Candace, is always trying to get the two in trouble with their mother for their schemes, but is never able to.