Here are some factors that complicate the count:
* Different types of "lead": Sometimes he played a character central to the plot but shared the screen time with another prominent actor.
* Early career roles: In some early films, he might not have been the absolute lead, but played significant supporting roles that later became known as "classic John Wayne".
* Western vs. other genres: Wayne is most closely associated with Westerns, but he starred in a variety of genres, including war films, comedies, and dramas.
However, a rough estimate suggests John Wayne starred in over 140 films**, with many of those being considered "lead roles".