How to Write Action Lines in a Screenplay

Action lines are everything in a screenplay that isn't dialogue: what we see, what we hear, what the characters do. They carry most of the reading experience, and they're where readers decide whether you can write. This guide covers the core rules, how to pace a scene on the page, before-and-after rewrites, and the mistakes that make a script feel heavy.

Updated September 2026 · 8 min read

1. What action lines are

Action lines, also called action, scene description or simply description, sit between the scene heading and the dialogue. They run the full width of the text area, start at the left margin, and are written in normal sentence case.

Action has three jobs: set the scene, show what the characters do, and control how fast the reader moves through the moment. Everything else in this guide serves those three jobs.

2. Present tense, active voice

A screenplay describes a film as it plays, so action is always written in the present tense. Not "Lena walked in," but "Lena walks in."

Prefer the active voice: the subject does the action. It's shorter, clearer and puts the character at the front of the sentence.

The "is running" form isn't wrong, and most writers use it now and then for something ongoing ("Snow is falling as she arrives"). Just don't make it your default. The simple present feels more immediate.

3. Write only what can be seen and heard

This is the most important rule. The audience can only see images and hear sounds, so the page should only describe images and sounds. A character's history, thoughts or feelings that aren't visible can't be filmed. Novelists call this interiority; screenwriters call it unfilmables.

An actor can't play "remembers the summer his father left." Turn the inner state into something visible: a behavior, a reaction, an object.

This rule has a sensible exception. Short touches of attitude that tell an actor or reader how a moment plays are widely accepted: "She smiles. It doesn't reach her eyes." Many writers also allow a line of voice or tone, especially in comedy. The test is whether it helps someone imagine the film, or whether it's information only a novel could deliver.

4. Short paragraphs and white space

Readers get through dozens of scripts a week, and dense blocks of text are the first thing that slows them down. Most writers keep action paragraphs to three or four lines at most, and many go shorter. White space on the page reads as speed.

One image or beat per paragraph

A useful rule of thumb: each paragraph covers one image, one action or one beat. When the focus shifts, start a new paragraph. Many readers treat each paragraph as roughly one shot, which is why this technique is sometimes called "directing on the page" without camera terms.

Pacing with line breaks

Line breaks control time. One long paragraph makes a moment feel continuous. Breaking it into single lines slows the reader down and makes each beat land. Use it for suspense, action and turning points, not for every scene.

The same content written as one sentence ("Lena reaches for the handle but stops when a shadow moves behind the glass, and steps back") is accurate, but the tension is gone.

5. Specific verbs over adverbs

"Walks quickly" is two words doing the work of one. Choose the verb that already contains the manner: hurries, strides, scurries, marches. Each paints a different person.

The same goes for vague nouns and filler. "Starts to," "begins to," "suddenly" and "very" rarely add anything. On screen, people don't begin to open doors; they open them.

6. Capitals for sounds and props

Traditionally, action lines use capital letters for a few things:

• A character's name the first time they appear, usually with an age: LENA (30s). This is near-universal. See introducing characters.
• Important sounds: a GUNSHOT, a phone RINGS, glass SHATTERS.
• Key props or visual effects that matter to the plot or to production.

Practice varies here more than anywhere else in action writing. Capitalizing sounds and props comes from shooting scripts, where departments scan for what they need. In a spec script, many writers capitalize only character introductions and the occasional key sound, and some skip sound capitals entirely. Nobody will reject a script for either choice. What does hurt is overuse: when every other word is in capitals, nothing stands out.

7. Camera directions and "we see"

In a spec script, the director decides the shots. Writing CLOSE ON, PAN TO or DOLLY IN in every scene reads as amateur and slows the page. You can suggest the shot through the writing itself:

A short isolated line like "The gun on the table" already implies a close shot. An occasional camera note is fine when a specific shot is essential to the story, such as an insert of a text message the audience must read.

"We see" and "we hear" are more debated. Many readers see them as filler, since everything in action is something we see. Others, including plenty of professional writers, use "we" occasionally to guide attention or to create a playful tone. The safe approach: cut "we see" by default, and keep it only when it genuinely helps a moment.

8. Before and after: a full rewrite

Here is a first-draft action block with most of the common problems in it:

Now the same moment, rewritten:

What changed: "we see" is gone, passive voice became active, adverbs became verbs, the unfilmable backstory ("worked at the diner for twenty years") became an image, the thought ("he wonders if she's in trouble") became a reaction, and one long paragraph became five short beats. The rewrite is barely longer, yet it plays like a scene.

9. Common mistakes

• Walls of text. Paragraphs of six, eight or ten lines. Break them up.
• Describing what can't be filmed: thoughts, backstory, memories, off-screen facts.
• Directing the actors line by line: every nod, sip and glance. Include only the gestures that matter.
• Over-describing locations. Give one or two telling details, not an inventory. The production designer does the rest.
• Dialogue hidden in action, such as "She tells him she's leaving." If it's said, write it as dialogue.
• Inconsistent character names in action and dialogue. If he's DANIEL in the cue, don't call him "the cook" three lines later.
• Transitions and camera terms everywhere. Use transitions sparingly and leave shots to the director.

Clean action also affects length: tight description keeps your page count honest, which matters because readers use it to estimate runtime. See screenplay length.

10. Frequently asked questions