The Closer. Although Kyra Sedgwick is the star, the entire cast of characters make contributions to the story in their own way. Each has a unique personna, each has faults and virtues, and if one of them were removed, the show would definitely be different. The same holds true of a novel.
There's an old saying in the theatre that there are no small parts, just small actors. In a novel, that's not necessarily true. Sometimes characters appear and disappear rapidly, and it's not necessary for the reader to remember their names or anything about them. Then again, sometimes a character that you might think was a "walk-on" reappears later in the story to assume a pivotal role.
Then there are the secondary leads. These may be friends and colleagues of the lead character or may fill the role of antagonist, opposing the protagonist, either openly or behind the scenes. In any case, their interaction with other characters, including the lead, can be critical.
Let's go back to my example of The Closer. There's the lead (Kyra Sedgwick, in her role of Brenda Leigh Johnson), and her husband, an FBI agent. The Chief of Police supplies drama because one never knows whether he'll side with or against Brenda. The detectives in her squad all have their good and bad qualities. Recently she's also been involved in a legal battle, which brings in both her attorney and the lawyer suing her and the Department. And so on. Everyone plays a part, and without any one of them, the whole would suffer.
Can you think of a book, play, or movie that had a really great ensemble cast? I'd love to hear your examples. Hope you'll share them.
Note: Tomorrow I'm guest blogging at The Introverted Reader in the section, "Saturdays In The South." Hope you'll check it out.