King Sejong's idea of making common people who had no opportunity of studying Chinese characters literate was very exceptional and reformative in the social atmosphere at that time, and it took a long time for the idea to be realized. First of all, the governing classes still maintained official literary lives using Chinese characters, and there was very slim chance for Han-geul to infiltrate through them. Instead, Han-geul slowly began to expand its influence by playing a role different from Chinese characters. As Han-geul was invented for common people, it played an important role among people at first. Although people who are capable of using Han-geul kept increasing among the governing classes, they rarely used Han-geul unless in an exceptional cases because they were using an official, privileged characters, Chinese characters and Chinese writings.

On the other hand, since common people had no choice, they gradually started to use Han-geul. The Han-geul message of King Sunjo shown above implies that Han-geul was widely spread among common people at that time. There was an event that shows not only common people but also more and more noble class people could read and write Han-geul. When a document written in Han-geul that criticizes the tyranny of Yonsangoon(연산군) appeared in 1504, Yonsangoon gave an order to ban learning Han-geul, to burn all the books in Han-geul and to report all the people who could use Han-geul.

It seems that the person who wrote the document was a noble man, and he intentionally used Han-geul in order to avoid exposure of his identity.
Women played an immense role in expansion of Han-geul use. Although many women were taught Chinese writings in noble classes, it seems that they gradually used Han-geul much. Therefore, they use Han-geul when exchanging letters with other women or with men. Also, many books mostly for women were published in Han-geul. This shows the important role of women in the expansion of Han-geul use as well.
Secondly, the role of Buddhism can't be ignored. Although Chosun Dynasty formally took the policy of respecting Confucianism and repressing Buddhism, Buddhism still kept an important position in common people's mind. Especially, the royal people who led invention and use of Han-geul like King Sejong and Sejo had strong belief in Buddhism.

Therefore, among many projects that can be done using Han-geul, they were enthusiastic in promoting translation and publication of Buddhist scriptures. Although the vassals made strong protests against their attempts to build Buddhist temple in the palace in a bid to hold worship in front of Buddha and publish Buddhist scriptures, these projects continually lasted throughout the time of King Sejong, Moonjong, and Sejo. Many Buddhist temples throughout the country went on publishing Buddhist scriptures afterward. Its purpose was to let common people realize the truth of Buddhism and die achieve their religious goals by reading Buddhist scriptures written in Han-geul.
In 17th and 18th century, novels contributed much in diffusion of Han-geul. Many people in the governing class were indulged in Chinese novels at that time. They read not the pure old literatures but love stories and popular novels and some noble people who read much of them used similar literary styles in their own writings as well. (This also gave an excuse to King Chungjo of enthronement(文體反正)) These novels were translated in Han-geul and widely read by common people, too. Han-geul novels were distributed in the form of transcription at first, but later they were published in imprinted forms (commercial publication) due to their commercial values.

These fashion of novels and rise of commercial publications were a sign of progress toward the modern times. Also, switching over from the medieval culture of emphasizing common literary language to the modern culture that values national language is entangled with it here. The positioning of Han-geul as a dominant character of Korea instead of Chinese character meant a progress towards the modern age.

Han-geul began to be used in official documents of the country by the Reform in the year of Kabo(갑오개혁), and the assertion that Korea could grow to a modern and strong country only if we used Han-geul instead of Chinese character became powerful. Even though it took a long time, the idea that King Sejong had in mind when he invented Han-geul eventually came true.