Scrooge's father was originally created by Carl Barks, who mentioned him in his 1950s Duck Family Tree notes, which described the relationship between the main members of Donald family from his comics. Barks gave Scrooge's father the name Old "Scotty" McDuck.
In the Donald Duck daily newspaper comic strip by Bob Karp and Al Taliaferro, Scrooge would sometimes refer to his rich father. In a 1960 installment of the strip, Scrooge says: "My daddy didn't trust banks", while digging up a chest full of cash from the McDuck property. In a later strip, Scrooge describes his father as "a lazy spendthrift who married a rich widow". In another strip, where Scrooge is talking to a homeless man who tells Scrooge that he quit school in the sixth grade, Scrooge responds: "What a coincidence! So did I! But dear old Dad left me twenty million to get started on!". Another strip has Scrooge showing Donald an antique chair that has been in his family for a hundred years, and says: "My father personally reupholstered it back in 1912!". When Donald accidentally breaks the chair's fabric, it turns out the chair was stuffed with money, to which Scrooge says the stuffing was cheap, since "it was tax-free then!".
In 1970's Zio Paperone e l'oro del Klondike ("Uncle Scrooge and the Gold of the Klondike"), drawn by Romano Scarpa, Scrooge's parents made their very first appearance. In a flashback sequence, Scrooge's father, referred to as Paperon-Papà in the original version, is a local shopkeeper who sells prospector equipment in the Klondike, and stores all his cash in a stove (not unlike how his future son would store his money in his Money Bin). In the story, he and Scrooge's mother, called Oretta Paporetta in Italian, have been dating for years, but did not get married, because both of them were too stingy to pay the local marriage fee of 1 dollar. Eventually, Scrooge's mother decides to pay the fee and the two ducks marry at last. The story also covers the birth of Scrooge McDuck and the first meeting between Rockerduck's parents.
In 1981, Mark Worden made an illustrated version of Carl Barks' 1950s Duck Family Tree notes, in which all relatives were given their own portrait. On this tree, Old 'Scotty' McDuck had a beard and wore a Scottish bonnet.
Fergus' name originates from the The Life and Times of Scrooge McDuck, in which he was a prominent character. In these flashback stories about Scrooge's youth, Fergus lives in Glasgow with his wife and children. The family is dirt poor, and Fergus encourages his son to work in order to earn his own money. Scrooge's obvious intelligence, skill at hard work and ambition make Fergus believe that Scrooge will be able to restore The Clan McDuck to its former glory.
Scrooge briefly mentioned his parents in the DuckTales episode "The Curse of Castle McDuck". When Scrooge returns to his childhood home, cottage McDuck, he reveals that his parents were poor, simple farmers.
Scrooge's parents made their animated debut in the season 1 episode "Once Upon a Dime", in which Scrooge refers to Fergus as McPapa. In this episode, it's told that Scrooge and his father both played the bagipes. McPapa, Scrooge and Scrooge's mother could be seen living in cottage McDuck, as it previously appeared in the series.
Fergus appears in the reboot. He was mentioned in the first episode "Woo-oo!" by Webby Vanderquack. Making his proper debut in "The Secret(s) of Castle McDuck!", Fergus is seen living in Castle McDuck, and acting as its laird. He and Downy are both still alive, having been cursed with immortality after Scrooge utilized discount mystic druid stones in the reconstruction of portions of Castle McDuck.
In The New Laird of Castle McDuck (Uncle Scrooge #289), young Scrooge returns to his family in Scotland, because there is a threat of the Clan's hereditary lands being seized due to Fergus' inability to pay the taxes. Using all of the money he has earned so far, 10,000 dollars, Scrooge is able to pay the taxes and becomes the new owner of their lands.
After years of hard work, Scrooge becomes rich in the Klondike and returns to Scotland as a billionaire, as shown in The Billionaire of Dismal Downs (Uncle Scrooge #293). Scrooge's original intention to settle in Dismal Downs quickly changes and Scrooge decides to move to Duckburg. Scrooge's sisters go with him, but Fergus decides to stay in Scotland.
According to William Van Horn's Travails (Uncle Scrooge #323), Fergus at some point had a short marriage with an unidentified woman, with whom he had one son: Rumpus McFowl. He later married Downy O'Drake, his wife in further stories, who became the mother of Scrooge and his sisters Matilda McDuck, and Hortense McDuck, whose names also origin from the Duck family tree sketches Barks did in the 1950s. Given the fact that Scrooge has a full brother called Gideon McDuck, Fergus and Downy must have had at least one other son.
In A Letter from Home (Uncle Scrooge #342), it's revealed that Fergus tried to find the Knight Templar treasure hidden in the castle McDuck by one of his ancestors, a Knight himself. Even though Fergus decided not to tell Scrooge about the treasure, the latter learns about it through other ways and, like his sister Matilda, thinks Fergus kept the secret from him because he disapproved Scrooge. In the middle of their way to the treasure Matilda finds a letter from Fergus revealing the reason he hid the secret from Scrooge is that Scrooge would feel better building his own fortune instead of inheriting one.