diff --git a/esphome/components/json/json_util.cpp b/esphome/components/json/json_util.cpp
index 40a3496981..e03f95fe7c 100644
--- a/esphome/components/json/json_util.cpp
+++ b/esphome/components/json/json_util.cpp
@@ -31,6 +31,7 @@ struct SpiRamAllocator : ArduinoJson::Allocator {
  protected:
   RAMAllocator<uint8_t> allocator_{RAMAllocator<uint8_t>(RAMAllocator<uint8_t>::NONE)};
 };
+
 #endif
 
 std::string build_json(const json_build_t &f) {
@@ -73,22 +74,14 @@ bool parse_json(const std::string &data, const json_parse_t &f) {
 JsonBuilder::JsonBuilder()
     : doc_(
 #ifdef USE_PSRAM
-          [this]() {
-            auto *alloc = new SpiRamAllocator();  // NOLINT(cppcoreguidelines-owning-memory)
-            allocator_ = alloc;
-            return alloc;
-          }()
+          (allocator_ = std::make_unique<SpiRamAllocator>(), allocator_.get())
 #else
           nullptr
 #endif
       ) {
 }
 
-JsonBuilder::~JsonBuilder() {
-#ifdef USE_PSRAM
-  delete static_cast<SpiRamAllocator *>(allocator_);  // NOLINT(cppcoreguidelines-owning-memory)
-#endif
-}
+JsonBuilder::~JsonBuilder() = default;
 
 std::string JsonBuilder::serialize() {
   if (doc_.overflowed()) {
diff --git a/esphome/components/json/json_util.h b/esphome/components/json/json_util.h
index 8eac87b10a..633e8182fb 100644
--- a/esphome/components/json/json_util.h
+++ b/esphome/components/json/json_util.h
@@ -25,6 +25,9 @@ std::string build_json(const json_build_t &f);
 /// Parse a JSON string and run the provided json parse function if it's valid.
 bool parse_json(const std::string &data, const json_parse_t &f);
 
+// Forward declaration to avoid exposing implementation details
+struct SpiRamAllocator;
+
 /// Builder class for creating JSON documents without lambdas
 class JsonBuilder {
  public:
@@ -42,13 +45,12 @@ class JsonBuilder {
   std::string serialize();
 
  private:
+#ifdef USE_PSRAM
+  std::unique_ptr<SpiRamAllocator> allocator_;  // One heap allocation, but keeps code clean
+#endif
   JsonDocument doc_;
   JsonObject root_;
   bool root_created_{false};
-  // Allocator must be last member to ensure it's destroyed after doc_
-#ifdef USE_PSRAM
-  void *allocator_{nullptr};  // Will store SpiRamAllocator*, managed in cpp file
-#endif
 };
 
 }  // namespace json