diff --git a/esphome/components/lvgl/__init__.py b/esphome/components/lvgl/__init__.py
index 19c258fcd5..c9cad1ac90 100644
--- a/esphome/components/lvgl/__init__.py
+++ b/esphome/components/lvgl/__init__.py
@@ -256,9 +256,11 @@ async def to_code(configs):
             True,
             type=lv_font_t.operator("ptr").operator("const"),
         )
+        # static=False because LV_FONT_CUSTOM_DECLARE creates an extern declaration
         cg.new_variable(
             globfont_id,
             MockObj(await lvalid.lv_font.process(default_font), "->").get_lv_font(),
+            static=False,
         )
         add_define("LV_FONT_DEFAULT", df.DEFAULT_ESPHOME_FONT)
     else:
diff --git a/esphome/cpp_generator.py b/esphome/cpp_generator.py
index 0478e45f7b..ddccb574e4 100644
--- a/esphome/cpp_generator.py
+++ b/esphome/cpp_generator.py
@@ -511,13 +511,17 @@ def with_local_variable(id_: ID, rhs: SafeExpType, callback: Callable, *args) ->
     CORE.add(RawStatement("}"))  # output closing curly brace
 
 
-def new_variable(id_: ID, rhs: SafeExpType, type_: "MockObj" = None) -> "MockObj":
+def new_variable(
+    id_: ID, rhs: SafeExpType, type_: "MockObj" = None, *, static: bool = True
+) -> "MockObj":
     """Declare and define a new variable, not pointer type, in the code generation.
 
     :param id_: The ID used to declare the variable.
     :param rhs: The expression to place on the right hand side of the assignment.
     :param type_: Manually define a type for the variable, only use this when it's not possible
       to do so during config validation phase (for example because of template arguments).
+    :param static: If True (default), declare with static storage class for optimization.
+      Set to False when the variable must have external linkage (e.g., to match library declarations).
 
     :return: The new variable as a MockObj.
     """
@@ -526,7 +530,7 @@ def new_variable(id_: ID, rhs: SafeExpType, type_: "MockObj" = None) -> "MockObj
     obj = MockObj(id_, ".")
     if type_ is not None:
         id_.type = type_
-    decl = VariableDeclarationExpression(id_.type, "", id_, static=True)
+    decl = VariableDeclarationExpression(id_.type, "", id_, static=static)
     CORE.add_global(decl)
     assignment = AssignmentExpression(None, "", id_, rhs)
     CORE.add(assignment)