Gideon grew up with his siblings in Scotland, as shown in Zio Paperone e le notizie... fraterne. According to his comic debut, he is also a member of the clan McDuck, and founded his successful newspaper (which has a gigantic office in Duckburg) "40 years ago". Gideon's newspaper notably has Jiminy Cricket as its mascot, representing the moralistic values of The County Conscience, as well as its constant hunt for the truth and honesty.
While he lacks his brother's love of gold (and even described his brother as a "money-grabbing robber baron" in his debut comic), Gideon values his morals and being honest to his readership, similar to the way his brother Scrooge treasures his fortune, and always knows exactly how many readers he has, similar to how Scrooge always knows exactly how much money he has. His primary goal is not to sell as many newspapers as possible, but to tell his readers the unfiltered truth. Gideon prides himself as the only independent news source in the state of Calisota (i.e. that has not been filtered through his brother). Gideon has an antagonistic relationship with his brother, who is jealous of Gideon's success, and often tries to buy Gideon's successful newspaper to get rid of the competition, only to be turned down every time. This is much to the frustration of Scrooge, as Gideon provides legit, honest competition, which Scrooge rarely gets.
Being the younger brother of the richest duck in the world, he often gets compared to his brother, much to Gideon's frustration. Instead, Gideon wants to be recognized by his own success and does not wish to be constantly associated with his wealthy brother.
Gideon is adamant on only giving his readers the "real news". His newspaper has a focus on crime-solving, which sometimes agitates the local police, who see him as meddlesome. Gideon has a strong dislike of trivial news like celebrity gossip and it infuriates him when the Duckburg public considers such things more newsworthy than important news like political events.
Gideon was introduced in the 1956 Donald Duck comic Shellfish Motives (Donald Duck #368-369), where he was one of the main characters. In this 50-page adventure, he employs his nephew Donald to find out the story behind a kidnapping for his newspaper. The story was written and drawn by classic Disney artist Romano Scarpa, who reused Gideon on multiple occasions. Throughout the years, Gideon has become one of the recurring members of the Duck family and has been used by various artists. Gideon often employs his relatives, such as his nephews Donald and Huey, Dewey, and Louie. In some of Gideon's more recent appearances, Dickie Duck (Glittering Goldie's granddaughter) works for him.
- Gideon holds the record of being the most-appearing McDuck after Scrooge, having appeared in more stories than Fergus, Matilda, Hortense, Douglas or any other character with the surname besides Scrooge.
- In some later appearances in Scarpa's works, Gideon's newspaper is referred to as "The Trumpet".
- His newspaper's original name is the Talking Cricket, the same as Jiminy Cricket.
- Gideon might have been inspired by a similar character from the Mickey Mouse newspaper strips: Goofy's uncle Gideon Goober (alias Uncle Giddy), who also runs a local newspaper and wears an outfit similar to Gideon's.
- According to his debut comic, Gideon's newspaper has a total of 4,275,421 readers.
- Gideon's debut comic (originally titled Paperino e i gamberi in salmì) appeared under the title Shellfish Motives in the first two IDW Donald Duck issues from 2015, thus marking Gideon's first appearance in American Disney media.
- In a 1966 installment of the long-running Donald Duck daily newspaper comic strip by Al Taliaferro and Bob Karp, Grandma Duck briefly mentions Scrooge's brother. When asked if Scrooge has ever given anyone anything in his life, Grandma responds that "When [Scrooge] was nine years old he gave his brother something...Chickenpox!" It is unknown whether this was meant to be a reference to Gideon or not.
- In Carl Barks's The Old Castle's Secret, Scrooge claims that he is the last living member of the Clan McDuck, which would mean he could not have a living sibling. However, Gideon McDuck is not the only living relative of Scrooge to carry the surname "McDuck" (others include Scrooge's sister, Matilda, and his first cousin, Douglas), and to therefore create the same inconsistency with The Old Castle's Secret. Barks himself even contradicted the statement in his later comic, A Christmas For Shacktown, in which Scrooge has an uncle named Jake McDuck.
- Gideon was not shown on Don Rosa's Donald Duck Family Tree. However, on Giovan Battista Carpi's Duck Family Tree, which was published a year later and is notable for containing a greater variety of characters (such as Titus McDuck and Grandpa Duck), Gideon was present.