Well, let's start with the common knowledge that once you start something successful, others will envy you and eventually try to imitate what you do. DC is known as a pioneer in the comics publishing industry, always the first to come up and try new ideas and eventually shape the industry that we know of today.
It was 1934, when DC was still known as Eastern Color Printing that the small outfit began printing reproductions of the comic strip "Famous Funnies" for a daily newspaper. What happened next was that King Comics and Popular Comics followed suit. Just a year later, Malcolm Wheeler-Nicholson, founder of National Allied Publications, became a pioneer in the comic industry when he published New Fun: The Big Comic Magazine #1 which became the first known comic book.
With this, he was able to acquire the talents of Vin Sullivan and Whitney Ellsworth to help create new and different characters. But then in 1938, the fledgling business fell into a huge debt to printing-plant owner and magazine distributor Harry Donenfeld. As fate would have it, Wheeler-Nicholson was forced to take him on as a partner in order to publish Detective #1 which created a separate entity which was named Detective Comics, Inc. Both men took on another partner, Jack S. Liebowitz who is Donenfield's accountant and named him as co-owner.
But monetary woes continued throughout the publication's first year and Nicholson was eventually forced to give up his ownership stake due to bankruptcy. By 1940, Detective Comics Inc. purchased National Allied Publishing at a bankruptcy auction and the two companies were merged to form National Comics. That same year also saw the creation of Superman, featured in Action Comics #1, which became a hit and thus solidified the company's status as a major comic book publishing company.
The DC circular logo then began to appear on all NAP and All American comics (this became a precursor for a future re-branding of the company name). Then Batman's character was created a year later with its debut feature in "The Case of the Chemical Syndicate" (Detective Comics #27), and the two superhero characters ultimately became the torch bearer to the company's name.
When the superheroes fad had fizzled out in the late 1940s, the company was forced to shift its focus on creating other stories to recoup their losses. It was an era wherein DC published crime and horror titles, as well as science fiction, Westerns, humor and romance. But publication of the company's most popular superhero titles still continued to augment their income. They also revived Flash in 1956 and introduced The Justice League of America into the DC lineup two years later (1958).
The succeeding years then saw a major reorganization of National Comics by incorporating its affiliates and everything else they own into one entity which was named the National Periodical Publications (NPP). To expand the company further, NPP opened up its doors and became publicly traded on the stock market in 1961.
In 1969, DC Comics became a subsidiary of Warner Bros. Entertainment and from then on, the company evolved into not just publishing comics but into producing merchandise featuring their well-known characters as well. The company's main characters; Superman, Batman, Wonder Woman, the Flash, Green Lantern, and the Justice League, became synonymous to the DC Comics image that these superhero characters represent.
A few highlights of DC's success in the 1970s also included Wonder Woman getting her own TV movie in 1974, and this was followed by a mini-series which was aired from 1975 to 1979. Furthermore, the first of four Superman films starred in by Christopher Reeve was released in 1978.
The year 1976 saw the arrival of Jenette Kahn as DC Comics' publisher which signaled a flurry of major changes to come. She was responsible for overhauling the entire company in 1977 when she changed the name from NPP to DC Comics Inc. and then created a new logo. When she became the company president five years later (1981), DC became the first comics company to pay royalties. Having a woman to help clean the house surely makes for good housekeeping...
From the 1980's onwards, DC continued its assault in the box-office theaters by releasing Superman II (1980), III (1983), and IV: The Quest for Peace (1988). The Supergirl film, Superman spin-off, was also released in 1984. A series of Batman movies were also released during the 1990's which gave the company a solid foothold in the industry.
With the tides on their favor, DC Comics Inc. went on to become the world's largest comic book publishing company especially when its chief rival, Marvel/Malibu went bankrupt. To date, DC Comics Inc. is recognized as the world's largest comic book company and is perhaps best known for being the first in everything related to the comics publishing industry.
The company's history is, in more ways than one, the actual basis for the history of American comic book publishing. Its dominance in the business, most notably during the 1990s when they hit it big on films and its enduring image, is a testament to the mass appeal and marketability of its comic book superheroes.