“Acting is reacting” is an old acting adage. The actor must react to what the other actors say and do, or to the conditions. The saying has been used both on the stage and in movies.
 
The film actor John Wayne (1907-1979) said “screen acting is reacting” in an interview in February 1949.
 
 
Wikipedia: John Wayne
Marion Mitchell Morrison (born Marion Robert Morrison; May 26, 1907 – June 11, 1979), better known by his stage name John Wayne, was an American film actor, director and producer. An Academy Award-winner, Wayne is the biggest box office draw of all time. An enduring American icon, he epitomized rugged masculinity and is famous for his demeanor, including his distinctive calm voice, walk, and height.
 
13 February 1949, Omaha (NE) World-Herald, “Looking at Hollywood” by Hedda Hopper, pg. 10F, col. 1:
“But, to me, screen acting is reacting. You come on the screen in a given situation, and the audience wants to see how you react to that. Sometimes training from stage coaching can be a handicap, not a help.”
(John Wayne—ed.)
 
Google News Archive
24 February 1950, Miami (FL) News, “Movie Tough Guy Forrest Tucker Cries Over Earl, Admits He’s Nuts” by Earl Wilson, pg. 6C, col. 1:
‘Very few actors can listen,” he said. “Somebody told me, maybe it was John Wayne, that ‘acting is reacting.’ I learned listening.”
   
Google Books
Everybody’s Book of Better Speaking
By Dorothy Uris
New York, NY: D. McKay
1960
Pg. 25:
Acting is reacting, an old theater axiom; and so with listening, on or off stage. Mind you, you don’t always have to come back with a quick retort; you may merely respond with an understanding look.
 
JSTOR
March 1961, The Tulane Drama Review, pg. 152:
Acting Is Reacting
By Dan W. Mullin
 
12 January 1964, New Orleans (LA) Times-Picayune, “Louisiana Blonde in NewStage Idea” by William Wolf, Dixie, pg. 9, col. 3:
One of the main principles of acting is reacting—looking at the other performer and taking cues from his face and attitude.
 
6 October 1964, Dallas(TX) Morning News, sec. 1, pg. 13:
TNT to Complete
Workshop Series
“Acting is Reacting” will be the subject of Raven Hail’s final of four workshop sessions on theater basics for Town North Theater at 8 p.m. Wednesday at Walnut Hill Recreation Center, Midway Road at Walnut Hill Lane.
 
3 October 1975, Daily Review (Hayward, CA), “Actor discusses getting started” by Laura Hitchcock, pg. 51, col. 2:
“All of your attention should be focused on your fellow actor. Acting is reacting.”
(Hal Smith—ed.)
   
Google News Archive
26 November 1984, Victoria (TX) Advocate, “Sam Waterston Takes Major Step With Role in ‘The Killing Fields’” by Bob Thomas (Associated Press Writer), pg. 10, col. 1:
“Wasn’t it Steve McQueen who said that the essence of film acting is reacting?”
     
The Internet Movie Database
Memorable quotes for
Mulholland Dr. (2001)
Jimmy ‘Woody’ Katz: Acting is reacting.
 
OCLC WorldCat record
Filmmaking for dummies
Author: Bryan Michael Stoller
Publisher: Hoboken, NJ : Wiley ; ©2009.
Edition/Format:  Book : English : 2nd ed
Contents:
Acting is reacting—
 
BroadwayWorld.com
TimeSquared
Which Musicals Do You Want to See the British/Menier ‘Minimalist’ Take On?
Posted On:5/11/10 at 09:03
Boybooshka, if you like it, and it works for you, that’s wonderful. My view though, is that a huge part of a good acting performance is listening. The old saying goes “acting is reacting.” I think that’s largely true, and I think you can’t really listen to your fellow actors if you’re listening to your fellow musicians, watching the conductor out of the corner of your eye and on top of it all, have an oboe in your mouth. It’s too many things to do at once.