The origin of the word "manga" is not well known, but we know who made it popular - Hokusai Katsushika a Japanese artist. Katsushika was a famous woodblock print artist (ukiyo-e) in the 1800s and he worked in many different styles; one of them was cartoon style illustrations for story books. He described this style as manga and the name remained.

One of the most famous "Thirty-six views of the Mount Fuji"
by Hokusai Katsushika (Painted in 1831-1834)

By the 20th century, with the opening of Japan doors to the outside world, the United States began trading with Japan. The Japanese picked up on the "comic strip" trend developing in America, and began drawing their own comic strips and caricatures. One of these was Ippei Okamoto, an artist. Okamoto began his own caricatures and comic strips. These first works were very much like the ones seen in the West. The only difference may have been in the reading. The manga strips were read right to left, rather than left to right as the Western comic strips. While the comic strip did take a little while to catch on in Japan, it was, like early Japanese animation influenced by Disney, a beginning that would have far-reaching consequences later on as it boomed into popularity.

Art & Culture of Japan