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".
Notably, 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 great variety of characters (such as Titus McDuck and Grandpa Duck), Gideon was present.
While he lacks interest in gold, 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. Gideon prides himself as the only independent news source in 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 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's newspaper notably has Jiminy Cricket as its mascot.
- 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 one of Al Taliaferro's newspaper strips, printed in 1966, 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...Chicken pox!" It is unknown whether this was meant to be a reference to Gideon or not.
- According to Carl Barks's The Old Castle's Secret, Scrooge is the last of the Clan McDuck, which would mean he couldn't have a living brother. 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 a similar inconsistency with The Old Castle's Secret.