Games in today's industry are no longer made in a smokey bedroom by an enthusiastic nerd with too much free time. They are developed by huge teams of individuals, all working on different aspects of the game. These different people can generally be categorized into either Programmers or Artists.
I'm working towards becoming a game artist, its what makes me feel good, so I wont talk about the programming side.
But its no good having 30 artists, who can't agree on how the game should look, and create content at all different levels of detail and style. This would result in the game being very visually disorganized, and scrappy.
So, to lead artistic rabble is/are the art director/s. The Art Directors role is to quality check all the work being produced, ensuring it is not only up to scratch, but that it suits the current style. The Art Director often also hires/fires, mentors the inexperienced, controls the direction of the art work and ensures everything is being completed on time.
In most organizations the art and programming directors look to the lead designers for direction, and so it is important to note that the Art director is by no means the highest role of management in the industry. However, a smaller company with a smaller workforce such as the company Introversion would have members sharing roles.
In a large company with many artists, the management aspect of the Art director becomes more emphasized and as a result the creative aspect of developing computer game content becomes left to the artists under the directors influence. This is where the split between being an artist and an art director becomes apparent and is often why some artists do not chose to move into management, favoring to stay on the artistic team as a lead artist.
The role of 'Art Director' does not exist only in games. There are Art Directors in the Film industry, Publishing, and generally any other type of creative industry. Many aspects of the role are similar. When comparing to film, an art director is still in control of the art produced, and is still in control of assigning tasks to the artists on the team, and ensuring that the tasks are completed to a high standard and on time. It is a very similar role throughout, as it is essentially and art management position.
There are many qualities that need to be present in an art director, but without a doubt the most important quality of an art director is experience. An art director must lead his team, and be able to spot flaws in any work. This can only be achieved if the art director in question has the experience to know what to change and what is not quite right.
An art director must also be a respected member of the team, this applies for any type of leadership position. A leader must lead, and have the confidence to know that their decisions are correct.
They must also be organized, as being an Art Director means they are no longer only organizing their own work, but everyone else too.
But once again, Experience, Experience, Experience, Skill.