diff --git a/esphome/components/esp32_ble/ble.cpp b/esphome/components/esp32_ble/ble.cpp
index d7d5976c0b..eb1d4148a3 100644
--- a/esphome/components/esp32_ble/ble.cpp
+++ b/esphome/components/esp32_ble/ble.cpp
@@ -265,9 +265,11 @@ bool ESP32BLE::ble_setup_() {
 
   if (this->name_ != nullptr) {
     if (App.is_name_add_mac_suffix_enabled()) {
+      // MAC address length: 12 hex chars + null terminator
+      constexpr size_t mac_address_len = 13;
       // MAC address suffix length (last 6 characters of 12-char MAC address string)
       constexpr size_t mac_address_suffix_len = 6;
-      char mac_addr[13];
+      char mac_addr[mac_address_len];
       get_mac_address_into_buffer(mac_addr);
       const char *mac_suffix_ptr = mac_addr + mac_address_suffix_len;
       name_with_suffix =
diff --git a/esphome/components/esp32_ble/ble.h b/esphome/components/esp32_ble/ble.h
index 0d34a7d5dd..72f182be05 100644
--- a/esphome/components/esp32_ble/ble.h
+++ b/esphome/components/esp32_ble/ble.h
@@ -192,12 +192,11 @@ class ESP32BLE : public Component {
   esphome::LockFreeQueue<BLEEvent, MAX_BLE_QUEUE_SIZE> ble_events_;
   esphome::EventPool<BLEEvent, MAX_BLE_QUEUE_SIZE> ble_event_pool_;
 
-  const char *name_{nullptr};
-
   // 4-byte aligned members
 #ifdef USE_ESP32_BLE_ADVERTISING
   BLEAdvertising *advertising_{};  // 4 bytes (pointer)
 #endif
+  const char *name_{nullptr};                 // 4 bytes (pointer to string literal in flash)
   esp_ble_io_cap_t io_cap_{ESP_IO_CAP_NONE};  // 4 bytes (enum)
   uint32_t advertising_cycle_time_{};         // 4 bytes
 
diff --git a/esphome/core/application.h b/esphome/core/application.h
index dae44d8902..14e800342e 100644
--- a/esphome/core/application.h
+++ b/esphome/core/application.h
@@ -105,11 +105,13 @@ class Application {
     arch_init();
     this->name_add_mac_suffix_ = name_add_mac_suffix;
     if (name_add_mac_suffix) {
+      // MAC address length: 12 hex chars + null terminator
+      constexpr size_t mac_address_len = 13;
       // MAC address suffix length (last 6 characters of 12-char MAC address string)
       constexpr size_t mac_address_suffix_len = 6;
-      const std::string mac_addr = get_mac_address();
-      // Use pointer + offset to avoid substr() allocation
-      const char *mac_suffix_ptr = mac_addr.c_str() + mac_address_suffix_len;
+      char mac_addr[mac_address_len];
+      get_mac_address_into_buffer(mac_addr);
+      const char *mac_suffix_ptr = mac_addr + mac_address_suffix_len;
       this->name_ = make_name_with_suffix(name, '-', mac_suffix_ptr, mac_address_suffix_len);
       if (!friendly_name.empty()) {
         this->friendly_name_ = make_name_with_suffix(friendly_name, ' ', mac_suffix_ptr, mac_address_suffix_len);