"I've been told I'm upstaging my scene partner. What does that mean, and what do I do about it? Or is this his problem?"
What is "upstaging" in theater?
Technically, "upstaging" means the practice of standing further upstage than your fellow actor(s), thus forcing them to turn away from the audience in order to look at you, which places them in a poor position from the audience's point of view. Colloquially, it means to "steal a scene" from another actor unfairly; that is, not because of a virtuoso performance, but by manipulation and a misapplication of craft or guile.
Certainly, upstaging—intentional or not—is a theatrical tradition, but one honored more in the breach than the observance. You shouldn't want to upstage anyone, just as you shouldn't want anyone doing it to you—not out of ego, but because it's counterproductive to good theatre.
An example of being upstaged
A classic (though perhaps apocryphal) example of the latter is the story of Marlon Brando as Marchbanks in summer stock. He set a glass of water half off a table just before exiting. This focused the audience's attention on whether or not the precariously perched glass would fall, and took their attention off Tallulah Bankhead, who played the next scene unaware that Brando had upstaged her with an inanimate object even while he himself was offstage. More often, upstaging manifests itself in a steady drift toward the back of the set.
Why you shouldn't upstage your fellow actors
Stage deportment and admonitions to "dress the stage" sound quaint today. While sensibilities change over time, these craft issues remain important in terms of properly focusing the action so that the audience is directed where to look in order to get the most out of the experience. While it's true that the audience members will always look where they want for their own individual reasons (she's beautiful; he's fascinating), it's the actor's job both to "live truthfully in the moment" and, at the same time, encourage the audience to look where the director intends (Stanislavski's "circles of concentration"). It's not "either/or," it's "not only/but also." A great example of this was Christopher Plummer's laser focus on the action during Broadway's "The Good Doctor." In this manner, he demanded that the audience look where he was looking: at the primary action of the play.
There are many advantages to exercising this element of the actor's craft. Not only is there the satisfaction of a job well done; the theatre experience for the audience is appreciably better because of these efforts. You have accomplished something of value and contributed positively on a nightly basis. Also—and in the realm of "enlightened self-interest"—the actor has a great deal of power when he or she is willing to give some away momentarily. Only when you're willing to "give" stage can you really "take" stage. If, for example, you turn slightly upstage in order to focus the audience's attention on someone else, you can "re-enter" simply by turning out. This allows you to recapture the audience's attention any time you want. If you've been still, the slightest movement can capture focus. If you refuse to give it up, you have nothing to take back and are relatively powerless. Of course, this is also basic acting: Is your focus on yourself, or on what you want and who can give it to you?
This is especially true in ensemble scenes when the text is distributed among several actors. How many times have you watched a play and been a beat behind the actors because by the time you figure out who's speaking, they're done? From the audience's point of view, it's like playing racquetball for the first time and running to where the ball just was rather than to where it is now. Not only is it confusing, it's frustrating, and it points out really quickly that you're at the mercy of actors unskilled at their craft.
The first acting advice I got (in high school) was: "Never turn your back on the audience." While that's wonderful advice metaphorically, it's nonsense when taken literally. (Remember Kevin Anderson and John Mahoney in "Orphans," when Harold forces Philip to breathe in the night air through the open window? An incredibly moving moment in the theatre with two still actors basically in tableau with their backs to the audience.) While anything can be turned into an affectation, you need to be comfortable in any body position.
Of course, we never want our craft to show, so we have to make sure that none of the above seems mannered or obvious. Everything needs to be motivated and incorporated organically. A countercross can't simply be dressing the stage; it needs to be an adjustment based on what another character just did (I'm turning upstage in order to see or hear you better).
Upstaging specifically does not mean taking the stage when it's "your turn" (meaning the character's). You're there for a reason, and even if you've got a small part, you need to deliver the goods effectively and on time. (Why did the author include this character?) Again, the mastery of craft and an understanding of the utilitarian aspects of your role help you to be confidently and appropriately bold, not worrying about upstaging another actor. If you've got a plot point to deliver, you need to make sure the audience gets it. If you've got a joke to set up, you'd better lay it out there clearly and cleanly or the punch line will fall flat. The stage is no place for the timid, and you can't be shy about "taking the stage." That's not the same as upstaging your fellow actors.
Knowledge is power, and when you understand the scene (as the playwright intended and as the director interprets it), you'll be able to differentiate for yourself when you're supposed to have primary focus and when you need to provide a supporting role. If it's clear that you're not "a stage hog" but a skillful, knowledgeable actor, you'll be able to make your case to your director and fellow actor(s) as needed. Then you won't have to worry about whether or not you're upstaging anyone.
Dan Carter is director of the Penn State University School of Theatre and producing artistic director of Pennsylvania Centre Stage. An actor and director (AEA, SAG, SSDC), he is a fight director and certified teacher in the Society of American Fight Directors and a former area liaison to Actors' Equity Association. He spent two terms on the Commission on Accreditation of the National Association of Schools of Theatre and is a former trustee of the National Theatre Conference.