diff --git a/index.html b/index.html
index 041e0300..09b05d51 100644
--- a/index.html
+++ b/index.html
@@ -13,8 +13,10 @@ <h1>⚾ 숫자 야구 게임</h1>
         올바른 예) 139 <br />
         틀린 예) 122
       </p>
-      <input type="text" id="user-input" />
-      <button id="submit">확인</button>
+      <form>
+        <input type="text" id="user-input" />
+        <button id="submit">확인</button>
+      </form>
       <h3>📄 결과</h3>
       <div id="result"></div>
     </div>
diff --git a/src/BaseballGame.js b/src/BaseballGame.js
new file mode 100644
index 00000000..6e386b1c
--- /dev/null
+++ b/src/BaseballGame.js
@@ -0,0 +1,78 @@
+// Controller
+export default class BaseballGame {
+  #DIGIT_LENGTH = 3;
+  #referee;
+
+  constructor(referee) {
+    this.#referee = referee;
+  }
+
+  play(computerInputNumbers, userInputNumbers) {
+    const isValidInput =
+      this.#validateInputNumbers(computerInputNumbers) &&
+      this.#validateInputNumbers(userInputNumbers);
+    if (!isValidInput) return "";
+
+    const judgement = this.#judge(computerInputNumbers, userInputNumbers);
+    const result = this.#formatResult(judgement);
+
+    return result;
+  }
+
+  // TODO: 널 오브젝트 패턴?? Judgeable을 validate하는 서비스로 추출
+  #validateInputNumbers(inputNumbers) {
+    const inputStr = String(inputNumbers);
+    if (!this.#validateCorrectLength(inputStr)) return false;
+    if (!this.#validateAllDigit(inputStr)) return false;
+    if (!this.#validateDuplication(inputStr)) return false;
+
+    return true;
+  }
+
+  #validateCorrectLength(input) {
+    return input.length === this.#DIGIT_LENGTH;
+  }
+
+  #validateAllDigit(input) {
+    return /^\d+$/.test(input);
+  }
+
+  #validateDuplication(input) {
+    return new Set(input).size === inputStr.length;
+  }
+
+  // TODO: Judgeable 객체를 두 개를 비즈니스 로직에 따라 처리하는 Referee 서비스로 추출
+  #judge(computerInputNumbers, userInputNumbers) {
+    const set = new Set();
+    let strike = 0;
+    let ball = 0;
+    const computerInputDigits = Array.from(
+      String(computerInputNumbers),
+      Number
+    );
+    const userInputDigits = Array.from(String(userInputNumbers), Number);
+
+    for (let i = 0; i < computerInputDigits.length; i++) {
+      if (computerInputDigits[i] === userInputDigits[i]) {
+        strike += 1;
+        continue;
+      }
+      set.add(computerInputDigits[i]);
+    }
+
+    for (const userInputDigit of userInputDigits) {
+      if (set.has(userInputDigit)) ball += 1;
+    }
+
+    return { strike, ball };
+  }
+
+  // TODO: VO 객체(Judge) 내의 로직으로 분리
+  #formatResult({ strike, ball }) {
+    if (strike === 0 && ball === 0) return "낫싱";
+    if (strike === this.#DIGIT_LENGTH) return "정답을 맞추셨습니다!";
+    if (strike === 0) return `${ball}볼`;
+    if (ball === 0) return `${strike}스트라이크`;
+    return `${ball}볼 ${strike}스트라이크`;
+  }
+}
diff --git a/src/index.js b/src/index.js
index 1553d753..a546b0f0 100644
--- a/src/index.js
+++ b/src/index.js
@@ -1,13 +1,76 @@
-export default function BaseballGame() {
-  this.play = function (computerInputNumbers, userInputNumbers) {
-    return "결과 값 String";
-  };
-}
-
-// export default class BaseballGame {
-//   play(computerInputNumbers, userInputNumbers) {
-//     return "결과 값 String";
-//   }
-// }
-
-new BaseballGame();
+import BaseballGame from "/src/BaseballGame.js";
+import {
+  convertDigitArrayToInt,
+  generateNonDuplicateRandomIntArray,
+} from "/src/utils.js";
+
+const generateComputerInputNumbers = () =>
+  convertDigitArrayToInt(
+    generateNonDuplicateRandomIntArray({
+      arraylength: 3,
+      digitCount: 1,
+    })
+  );
+
+const userInputEl = document.querySelector("#user-input");
+const submitBtnEl = document.querySelector("#submit");
+const resultEl = document.querySelector("#result");
+
+const baseballGame = new BaseballGame();
+let computerInputNumbers = generateComputerInputNumbers();
+
+const resetUserInput = () => {
+  userInputEl.disabled = false;
+  userInputEl.value = null;
+  userInputEl.focus();
+};
+
+const resetResultEl = () => {
+  resultEl.innerHTML = "";
+};
+
+const showWinningResult = () => {
+  const strongEl = document.createElement("strong");
+  strongEl.textContent = result;
+  resultEl.textContent = "";
+  resultEl.appendChild(strongEl);
+
+  const restartMention = document.createElement("span");
+  restartMention.textContent = "게임을 새로 시작하시겠습니까?";
+
+  const restartButtonEl = document.createElement("button");
+  restartButtonEl.textContent = "게임 재시작";
+  restartButtonEl.addEventListener("click", handleRestart);
+
+  const restartWrapper = document.createElement("div");
+  restartWrapper.appendChild(restartMention);
+  restartWrapper.appendChild(restartButtonEl);
+
+  resultEl.appendChild(restartWrapper);
+};
+
+const handleRestart = (e) => {
+  resetUserInput();
+  resetResultEl();
+  computerInputNumbers = generateComputerInputNumbers();
+};
+
+const handleSubmit = (e) => {
+  const userInputNumbers = Number(userInputEl?.value);
+  const result = baseballGame.play(computerInputNumbers, userInputNumbers);
+
+  if (!result) {
+    alert("유효하지 않은 입력입니다.");
+    userInputEl.focus();
+    return;
+  }
+  if (result === "정답을 맞추셨습니다!") {
+    userInputEl.disabled = true;
+    showWinningResult();
+    return;
+  }
+
+  resultEl.textContent = result;
+};
+
+submitBtnEl.addEventListener("click", handleSubmit);
diff --git a/src/utils.js b/src/utils.js
new file mode 100644
index 00000000..24140575
--- /dev/null
+++ b/src/utils.js
@@ -0,0 +1,27 @@
+export const convertDigitArrayToInt = (digitArr) => parseInt(digitArr.join(""));
+
+export const generateRandomInt = (length = 1) => {
+  const min = 10 ** (length - 1);
+  const max = 10 ** length;
+
+  return Math.floor(Math.random() * (max - min)) + min;
+};
+
+export const generateFixedSizeSet = (generateValue, { size = 1 }) => {
+  const set = new Set();
+  while (set.size < size) {
+    const value = generateValue();
+    set.add(value);
+  }
+  return set;
+};
+
+export const generateNonDuplicateRandomIntArray = ({
+  arraylength,
+  digitCount = 1,
+}) =>
+  Array.from(
+    generateFixedSizeSet(() => generateRandomInt(digitCount), {
+      size: arraylength,
+    })
+  );