As of yet, Rockerduck has never made an animated appearance.
In the Uncle Scrooge comic comic Zio Paperone e l'oro del Klondike ("Unce Scrooge and the Gold of the Klondike"), drawn by Romano Scarpa, we learn more about Rockerduck's family. This story is the eleventh chapter of the Italian comic book series Storia e gloria della dinastia dei paperi, which shows the history of the McDucks (and their rivalry with the Rockerducks) from the ancient Egyptians to the present date. In the story, Rockerduck's rich and unmarried father moves to the Klondike to have revenge on Scrooge McDuck's father for an incident between their fathers that happened years before. After a dogsled chase on the slippery hills of Alaska, both rivals end up in the hospital, where Rockerduck falls in love with his golddigger nurse, with whom he has a baby: John D. Rockerduck. Rockerduck's parents reappeared years later in the The Life and Times of Scrooge McDuck comic series, in which Rockerduck's father's full name was revealed to be Howard Rockerduck.
Rockerduck's little nephew Arsène Rockerduck appeared in the 1972 comic Paperino e l'isola col singhiozzo; while George, Patrick, and Simeon (Rockerduck's triplet nephews) made their comic debut in Castles in the Sand (first published in 1984). Rockerduck was also shown to have a nephew called Ricky Rockerduck in a later Uncle Scrooge comic.
As revealed in the Uncle Scrooge comic Most Helpful Aunt Eider, Rockerduck and Scrooge have a common relative: their old and near-sighted aunt Eider. Aunt Eider became a recurring character afterwards.
Like his rival, Rockerduck is a shrewd businessman and has managed to organize a worldwide financial empire that can easily rival those of Scrooge and Flintheart Glomgold. Unlike them, he is not a tightwad but much more a liberal spender (but by no means a squanderer). He seems to maintain that "you have to spend money to make money"; this trait makes him a natural antagonist to Scrooge, who is capable of going to absurd lengths to spare even trivial sums of money. Rockerduck has a taste for luxury, and likes to show off his wealth. Besides his secretary, advisor, and right-hand man Jeeves, he does not seem to have any close confidants.
Like Scrooge and Flintheart, Rockerduck is extremely competitive. He is rivaling them in the wealth department and has occasionally claimed the titles of "The Richest Duck in the World" and "The Second Richest Duck in the World". He is an influential member of the Billionaires' Club of Duckburg, of which Scrooge and Flintheart are also members. Only three stories feature him and Flintheart both, though: Zio Paperone e il bisbilione ("Uncle Scrooge earns a billion"), Whatever Happened to Scrooge McDuck? (where Rockerduck and Glomgold both make a cameo in a future vision that shows both of them having been made bankrupt by Donald's Duck charity company) and the 126 page counting comic story Zio Paperone e l'ultima avventura ("Uncle Scrooge and the Last Adventure", first published in 2013; localized as "Scrooge's Last Adventure" in 2016), Rockerduck and Flintheart Glomgold finally decide to combine their powers and work together against Scrooge (alongside the Beagle Boys and Magica).
Another possible distinction between Scrooge and Rockerduck is their country of residence and where their investments lie. In contrast to the Scottish birth of Scrooge, Rockerduck claims to be hailing from England, where he is sometimes depicted to be living, and shown to be the more active in Europe than in America, with some stories having Scrooge having to buy land from him or compete with him to be able to expand his businesses on the European markets. This is often ignored in other stories to be able to have the rivals meet on a daily basis as in the case of Scrooge's other rival, Flintheart Glomgold (who in the Barks stories lives in South Africa) with John primarily managing his activities from a large business building he owns in Duckburg, and the three characters sitting at the same table in the Billionaires' Club of the city.
Rockerduck also has a passion for collecting. Besides his valuable coins and stamp collection, he is also the owner of an extensive art collection, including artifacts created from antiquity through to the 20th century. Since Scrooge also has collections of the same theme and similar value, many of their confrontations center on them trying to obtain a new addition to their collections.
On a more personal level, Scrooge and Rockerduck seem to bicker constantly, criticizing each other's ways of life and personal faults. Although his confrontations with Scrooge have often found him defeated or even humiliated, he has commented on at least enjoying the challenge that Scrooge presents to him. At times the two find each other co-operating to achieve common goals. If they are worthy rivals to each other, they also seem to make effective partners—but only on a temporary basis. Some stories portray Rockerduck in a more positive light and portray him as friendly towards Scrooge's associates like Brigitta McBridge and Donald Duck, as he has nothing personal against them. When relaxed he can even be a pleasant companion for them or Scrooge. In all these traits, he differs from Flintheart Glomgold.
Rockerduck was created by Carl Barks, who used him in his comic Boat Buster (first published in 1961). In this story, Rockerduck is portrayed as an oil tycoon who argues with Scrooge McDuck over which one of them makes the best gasoline. To settle this, Scrooge and John agree each one to enter a boat at an upcoming race. Scrooge is so confident of his victory he says he could win regardless of who is driving his boat. Trying to prove his point, Scrooge randomly picks somebody from the crowd watching their argument but completely loses confidence when that somebody happens to be his unlucky nephew Donald Duck. To increase his chances of victory, Scrooge sees to it that all other boats in the race were powered by his gasoline. Near the end, several boats (Donald's included) have crashed and a loose motor push Donald into the finish line in the first place. Scrooge claims victory, but Rockerduck points out they first must find out whose gasoline was powering that motor. Despite the odds being for Scrooge, the motor happens to be the one powered by John Rockerduck's gasoline.
The character has rarely appeared in American stories but appears regularly in Brazilian and European stories, and especially in Italian ones. He also appeared in stories produced by the now defunct Disney Studio Program. His first appearance in an Italian story was Zio Paperone e il kiwi volante, first published on March 1, 1963. After this, the Disney Studio Program developed the character, and since then the Italian creators have further developed Rockerduck and explored various aspects of his relationship with Scrooge.
Many of the stories presenting him, especially during the 1970s and the 1980s, compare and contrast his and Scrooge's methods of organizing their business in order to gain profit. Some of those methods include researching new products for their industries, ways of refining and improving the existing ones, and the study of new producing methods. Also ways of improving their marketing techniques and public relations, in order to increase sales, or even trying to improve the ratings of their TV stations and the sales of their newspapers, in order to have more clients paying for advertisements in them. Both he and Scrooge try to predict each other's moves in order to act accordingly. In his efforts, Rockerduck often resorts to industrial espionage or sabotage. Although less often, Scrooge occasionally uses the same methods. Sometimes Rockerduck's plans against Scrooge involve more severe actions like abduction, hijacking his planes or blackmailing him. On these occasions he usually lets his right-hand man Jeeves do the dirty work, but he also hires the Beagle Boys to do his dirty work for him from time to time.
In a 2007 issue of Uncle Scrooge which was clearly a nod to the Earth-A of Marvel Comics, Scrooge is convinced to take a holiday on "Earth-D" by his counterpart "Scrooge-B". In this alternate reality a discouraged Scrooge is heavily in debt to several creditors; one being Rockerduck. The alternate Rockerduck has no visible businesses save for a greengrocery which he manages, and says that he made a mistake investing in the failing McDuck stock. When "Scrooge-A" works to get his counterpart's business back on track, he retires the debt to Rockerduck, and also buys the produce store, keeping John D. Rockerduck on board as proprietor. Rockerduck admits that although it was odd to be part of McDuck's recovering business empire, he also says "it makes me feel almost like the free-spending tycoon I used to be!"
In 2011, Boom! Studios released a short-lived DuckTales comic book that had an intertwining story with their already successful Darkwing Duck comic. In the first story arc, Rightful Owners, Rockerduck appeared as a main antagonist who attempts to trick Scrooge into returning all of his priceless artifacts and longtime of rival of Scrooge's as in his other comic appearances. This is in spite of him never having appeared in the animated series, his antagonistic role largely having been given to Flintheart Glomgold.
Rockerduck has a cameo in issue #8 of Joe Books' Darkwing Duck comic. In Dean Tightbill's flashback, he explains that he got the money to found Nutricide Inc. from some "morally flexible investors"; in the accompanying illustration, he is shown receiving that money from Steelbeak, alongside a silhouetted Glomgold and Rockerduck.
- Rockerduck has a habit of eating his hat whenever he is defeated by Scrooge. This has led in some stories to Rockerduck eating an entire truckload of hats because of an especially abject defeat.
- Despite not appearing physically in the DuckTales show, his habit of eating his hat when defeated by Scrooge is referenced in "Wrongway in Ronguay", in which Flintheart Glomgold, Scrooge's main rival and the primary antagonist in the series, has to do this after losing the bet he made with Scrooge. Also, in the DuckTales episode "The Unbreakable Bin", there is a picture of a duck on Scrooge's wall that looks a lot like Rockerduck. And in "Super DuckTales", while Ma Beagle has Scrooge's Mansion she throws a party, one the guests is named Rockerfeather.
- In the Danish stories, he is named "Andy Anderbilt". It might be a reference to Cornelius Vanderbilt.