According to Jim Collins, the "highly capable individual" level is the first level on the path to becoming a true leader. At this level, the person is not really a leader in the sense of supervising other people. Instead, this is a person who is showing that they have the potential to someday be a leader. This person might, however, be able to lead his/her peers by example.
The reason for this is that this person is someone who can help their organization by using their skills, their talent, their knowledge, and their good work habits. An example of such a person would be a retail sales person who works hard and learns all of the ins and outs of the job very quickly. Such a person might inspire his/her coworkers to work harder and become more proficient at their jobs. Such a person might get noticed by management and be given a chance to move up to a higher level in the firm hierarchy.