Voiced by British actor Thomas Sangster on Phineas and Ferb's original run and American actor David Errigo Jr. since 2018, with a singing voice by series composer Danny Jacob, he was created by Phineas and Ferb co-founders Dan Povenmire and Jeff "Swampy" Marsh.

They are featured in the majority of episodes as the A-Plot constructing large scale inventions or taking part in other outlandish activities.

Ferb comes from a blended family, a premise the creators considered underused in children's programming and which reflected Marsh's own upbringing.

[8] Throughout their summer vacation, Ferb and Phineas conceive outrageous schemes to defeat boredom while sitting lazily beneath a tree in their backyard.

[15] Phineas and Ferb was inspired by their boyhood memories of summer vacation;[9] Povenmire and Marsh both felt the theme of school in television had fallen to redundancy and wanted to create a series that took place solely in the summertime.

"[22] Instead, he and his brother create things for the sheer enjoyment of it[22] or to help out others ("and for the ladies"); for example, Ferb and Phineas carve Candace's face into Mount Rushmore for her birthday,[23] set up a roller derby for a rematch race with his Grandmother Betty Jo's old rival,[24] create a haunted house for their friend Isabella to cure her hiccups and make a super-computer to find out what to do for their mom after being so kind to them.

"[26] In the original pitch to overseas The Walt Disney Company executives, Povenmire and Marsh constructed storyboards and recorded them with dialogue and sound effects.

[9] However, after considering comedy's "big duos" including Wallace and Gromit and Jay and Silent Bob, the creators chose to have Ferb speak at least once in most episodes (but in "Summer Belongs To You" he spoke nine times and in "The Lizard Whisperer" gives an entire short speech that lasts about 45 seconds), but to have him remain silent and allow Phineas to speak for him the majority of the time.

[4] Although Ferb's taciturnity is generally not commented on in the series, Phineas mentions it while he and his brother were in England on the episode "A Hard Day's Knight": "I'll be the top half since I tend to do more of the talking and you will be on the bottom part because of your long spindely legs".

Jean Yoo, an official press member for Disney Channel, notes that when Ferb does speak, "it always shows a greater understanding of the situation than his countenance would indicate.

[citation needed] He usually says one sentence per episode,[6] such as "Platypuses are the only mammals to lay eggs,"[3] "Well, he [Buford] was all up in my face,"[28] or "Candace, we [Phineas and Ferb] are just kids."

Emily Ashby of Common Sense Media describes him as a "go-to engineering guru" and considers him and Phineas to be "partner[s] in crime.

"[30] Susan Stewart, reviewing the show in The New York Times, notes that Phineas and Ferb "work on a heroic scale and are apparently not limited by the laws of nature.

"[32] Ed Stetzer, Richie Stanley, and Jason Hayes, author's the book Lost and Found: The Younger Unchurched and the Churches That Reach Them, wrote that Ferb and Phineas, along with the cast of High School Musical, are examples of creating a "whole new culture" in households.

[35] Ferb is also credited as the singer in the music video version of "My Ride from Outer Space" from the episode "The Chronicles of Meap" (actually performed again by Danny Jacob).

[4] Costumed versions of Ferb and Phineas have appeared in Disneyland, for the pre-taping of the annual Walt Disney World Christmas Day Parade.