Very simply, accordionists are people who play the accordion. An accordion is a rectangular musical instrument that is played by compressing and expanding the instrument while also pressing a series of buttons or keys to create a certain sound. Accordions are also sometimes referred to as "squeeze boxes."
One of the interesting thing about being an accordionist is that you can choose to be independent as a musician or part of a larger musical group. Accordions are considered to be "one man band" instruments in that complete songs can be played independent of other musical accompaniment. However, they can also be played along with other instruments.
While accordionists can decide to have completely solo careers, it is also possible for them to to be part of a band. Although the accordion is not a particularly common instrument in popular music today, it was more commonly used in popular music in the first half of the 20th Century. Accordions have been used sporadically in popular music more recently. Tom Waits, They Might Be Giants, and Nirvana have all used accordions in their music. The most famous accordion player of the last century was "Weird Al" Yankovik who is famous for his spoofs of other popular songs. He has played the accordion on every one of his albums.
Accordionists can also decide to focus on folk music. The accordion is a common musical instrument in the folk music traditional to countries in North America, South America, and Europe. Accordionists who play in folk bands are likely to spend much of their time making new recordings of old standards and playing at both music and cultural festivals.
Furthermore, some classical music written for orchestras includes parts for accordionists. Therefore, just like many other instruments, the accordion can be played as part of popular, folk, and even classical music. Although it is not a particularly common instrument, it is called for in many kinds of music and offers accordionists a range of career choices.
Like many musicians who play unusual instruments, many accordionists teach as well as perform. Although there are not droves of people searching for an accordion instructor, there are certainly a few. In fact, it is common for people who play other instruments to decide to add the accordion to their repertoire. Hence the need for accordion instructors. Furthermore, as accordions are rather uncommon, there are not very many people who know how to service them. Some accordionists repair and service accordions in addition to playing them.