diff --git a/esphome/components/logger/__init__.py b/esphome/components/logger/__init__.py
index c8f3c52911..264197c175 100644
--- a/esphome/components/logger/__init__.py
+++ b/esphome/components/logger/__init__.py
@@ -329,10 +329,11 @@ async def to_code(config):
     level = config[CONF_LEVEL]
     CORE.data.setdefault(CONF_LOGGER, {})[CONF_LEVEL] = level
     initial_level = LOG_LEVELS[config.get(CONF_INITIAL_LEVEL, level)]
+    tx_buffer_size = config[CONF_TX_BUFFER_SIZE]
+    cg.add_define("ESPHOME_LOGGER_TX_BUFFER_SIZE", tx_buffer_size)
     log = cg.new_Pvariable(
         config[CONF_ID],
         baud_rate,
-        config[CONF_TX_BUFFER_SIZE],
     )
     if CORE.is_esp32:
         cg.add(log.create_pthread_key())
diff --git a/esphome/components/logger/logger.cpp b/esphome/components/logger/logger.cpp
index 22a95e4835..497809cd2e 100644
--- a/esphome/components/logger/logger.cpp
+++ b/esphome/components/logger/logger.cpp
@@ -152,10 +152,7 @@ inline uint8_t Logger::level_for(const char *tag) {
   return this->current_level_;
 }
 
-Logger::Logger(uint32_t baud_rate, size_t tx_buffer_size) : baud_rate_(baud_rate), tx_buffer_size_(tx_buffer_size) {
-  // add 1 to buffer size for null terminator
-  // NOLINTNEXTLINE(cppcoreguidelines-owning-memory) - allocated once, never freed
-  this->tx_buffer_ = new char[this->tx_buffer_size_ + 1];
+Logger::Logger(uint32_t baud_rate) : baud_rate_(baud_rate) {
 #if defined(USE_ESP32) || defined(USE_LIBRETINY)
   this->main_task_ = xTaskGetCurrentTaskHandle();
 #elif defined(USE_ZEPHYR)
@@ -196,7 +193,7 @@ void Logger::process_messages_() {
     uint16_t text_length;
     while (this->log_buffer_->borrow_message_main_loop(message, text_length)) {
       const char *thread_name = message->thread_name[0] != '\0' ? message->thread_name : nullptr;
-      LogBuffer buf{this->tx_buffer_, this->tx_buffer_size_};
+      LogBuffer buf{this->tx_buffer_, ESPHOME_LOGGER_TX_BUFFER_SIZE};
       this->format_buffered_message_and_notify_(message->level, message->tag, message->line, thread_name,
                                                 message->text_data(), text_length, buf);
       // Release the message to allow other tasks to use it as soon as possible
diff --git a/esphome/components/logger/logger.h b/esphome/components/logger/logger.h
index 8bf1edebb8..90722ee79c 100644
--- a/esphome/components/logger/logger.h
+++ b/esphome/components/logger/logger.h
@@ -143,7 +143,7 @@ enum UARTSelection : uint8_t {
  */
 class Logger : public Component {
  public:
-  explicit Logger(uint32_t baud_rate, size_t tx_buffer_size);
+  explicit Logger(uint32_t baud_rate);
 #ifdef USE_ESPHOME_TASK_LOG_BUFFER
   void init_log_buffer(size_t total_buffer_size);
 #endif
@@ -281,7 +281,7 @@ class Logger : public Component {
   inline void HOT log_message_to_buffer_and_send_(bool &recursion_guard, uint8_t level, const char *tag, int line,
                                                   FormatType format, va_list args, const char *thread_name) {
     RecursionGuard guard(recursion_guard);
-    LogBuffer buf{this->tx_buffer_, this->tx_buffer_size_};
+    LogBuffer buf{this->tx_buffer_, ESPHOME_LOGGER_TX_BUFFER_SIZE};
 #ifdef USE_STORE_LOG_STR_IN_FLASH
     if constexpr (std::is_same_v<FormatType, const __FlashStringHelper *>) {
       this->format_log_to_buffer_with_terminator_P_(level, tag, line, format, args, buf);
@@ -312,7 +312,6 @@ class Logger : public Component {
 
   // Group 4-byte aligned members first
   uint32_t baud_rate_;
-  char *tx_buffer_{nullptr};
 #if defined(USE_ARDUINO) && !defined(USE_ESP32)
   Stream *hw_serial_{nullptr};
 #endif
@@ -354,7 +353,6 @@ class Logger : public Component {
 #endif
 
   // Group smaller types together at the end
-  uint16_t tx_buffer_size_{0};
   uint8_t current_level_{ESPHOME_LOG_LEVEL_VERY_VERBOSE};
 #if defined(USE_ESP32) || defined(USE_ESP8266) || defined(USE_RP2040) || defined(USE_ZEPHYR)
   UARTSelection uart_{UART_SELECTION_UART0};
@@ -371,6 +369,9 @@ class Logger : public Component {
   bool global_recursion_guard_{false};  // Simple global recursion guard for single-task platforms
 #endif
 
+  // Large buffer placed last to keep frequently-accessed member offsets small
+  char tx_buffer_[ESPHOME_LOGGER_TX_BUFFER_SIZE + 1];  // +1 for null terminator
+
   // --- get_thread_name_ overloads (per-platform) ---
 
 #if defined(USE_ESP32) || defined(USE_LIBRETINY)
diff --git a/esphome/components/logger/logger_esp32.cpp b/esphome/components/logger/logger_esp32.cpp
index 9d64771aec..d6ad77ff4f 100644
--- a/esphome/components/logger/logger_esp32.cpp
+++ b/esphome/components/logger/logger_esp32.cpp
@@ -89,16 +89,16 @@ void Logger::pre_setup() {
     switch (this->uart_) {
       case UART_SELECTION_UART0:
         this->uart_num_ = UART_NUM_0;
-        init_uart(this->uart_num_, baud_rate_, tx_buffer_size_);
+        init_uart(this->uart_num_, baud_rate_, ESPHOME_LOGGER_TX_BUFFER_SIZE);
         break;
       case UART_SELECTION_UART1:
         this->uart_num_ = UART_NUM_1;
-        init_uart(this->uart_num_, baud_rate_, tx_buffer_size_);
+        init_uart(this->uart_num_, baud_rate_, ESPHOME_LOGGER_TX_BUFFER_SIZE);
         break;
 #ifdef USE_ESP32_VARIANT_ESP32
       case UART_SELECTION_UART2:
         this->uart_num_ = UART_NUM_2;
-        init_uart(this->uart_num_, baud_rate_, tx_buffer_size_);
+        init_uart(this->uart_num_, baud_rate_, ESPHOME_LOGGER_TX_BUFFER_SIZE);
         break;
 #endif
 #ifdef USE_LOGGER_USB_CDC
diff --git a/esphome/components/logger/logger_host.cpp b/esphome/components/logger/logger_host.cpp
index be12b6df6a..fe094f6e9e 100644
--- a/esphome/components/logger/logger_host.cpp
+++ b/esphome/components/logger/logger_host.cpp
@@ -5,8 +5,8 @@ namespace esphome::logger {
 
 void HOT Logger::write_msg_(const char *msg, uint16_t len) {
   static constexpr size_t TIMESTAMP_LEN = 10;  // "[HH:MM:SS]"
-  // tx_buffer_size_ defaults to 512, so 768 covers default + headroom
-  char buffer[TIMESTAMP_LEN + 768];
+  static constexpr size_t HEADROOM = 128;      // Extra space for ANSI codes, newline, etc.
+  char buffer[TIMESTAMP_LEN + ESPHOME_LOGGER_TX_BUFFER_SIZE + HEADROOM];
 
   time_t rawtime;
   time(&rawtime);
diff --git a/esphome/core/defines.h b/esphome/core/defines.h
index 02335e2745..1128df94f0 100644
--- a/esphome/core/defines.h
+++ b/esphome/core/defines.h
@@ -21,6 +21,7 @@
 
 // logger
 #define ESPHOME_LOG_LEVEL ESPHOME_LOG_LEVEL_VERY_VERBOSE
+#define ESPHOME_LOGGER_TX_BUFFER_SIZE 512
 #define USE_LOG_LISTENERS
 #define ESPHOME_LOG_MAX_LISTENERS 8
 
diff --git a/tests/dummy_main.cpp b/tests/dummy_main.cpp
index e6fe733807..52f1fbd319 100644
--- a/tests/dummy_main.cpp
+++ b/tests/dummy_main.cpp
@@ -13,7 +13,7 @@ using namespace esphome;
 
 void setup() {
   App.pre_setup("livingroom", "LivingRoom", false);
-  auto *log = new logger::Logger(115200, 512);  // NOLINT
+  auto *log = new logger::Logger(115200);  // NOLINT
   log->pre_setup();
   log->set_uart_selection(logger::UART_SELECTION_UART0);
   App.register_component(log);