diff --git a/src/main/java/com/bmilab/backend/domain/user/controller/AdminUserApi.java b/src/main/java/com/bmilab/backend/domain/user/controller/AdminUserApi.java
index 817b9c8e..6b514751 100644
--- a/src/main/java/com/bmilab/backend/domain/user/controller/AdminUserApi.java
+++ b/src/main/java/com/bmilab/backend/domain/user/controller/AdminUserApi.java
@@ -2,6 +2,7 @@
 
 import com.bmilab.backend.domain.user.dto.request.RegisterUserRequest;
 import com.bmilab.backend.domain.user.dto.request.AdminUpdateUserRequest;
+import com.bmilab.backend.domain.user.dto.request.UpdateUserStatusRequest;
 import com.bmilab.backend.domain.user.dto.request.UserAccountEmailRequest;
 import com.bmilab.backend.domain.user.dto.response.UserDetail;
 import com.bmilab.backend.global.exception.ErrorResponse;
@@ -95,4 +96,49 @@ ResponseEntity<Void> sendAccountEmail(
             @PathVariable Long userId,
             @RequestBody UserAccountEmailRequest request
     );
+
+    @Operation(summary = "사용자 퇴사 처리", description = "사용자를 퇴사 처리하는 PATCH API. 퇴사 처리된 사용자는 로그인할 수 없습니다.")
+    @ApiResponses(
+            value = {
+                    @ApiResponse(
+                            responseCode = "200",
+                            description = "퇴사 처리 성공"
+                    ),
+                    @ApiResponse(
+                            responseCode = "400",
+                            description = "관리자 계정은 퇴사 처리할 수 없습니다.",
+                            content = @Content(schema = @Schema(implementation = ErrorResponse.class))
+                    ),
+                    @ApiResponse(
+                            responseCode = "404",
+                            description = "사용자 정보를 찾을 수 없습니다.",
+                            content = @Content(schema = @Schema(implementation = ErrorResponse.class))
+                    )
+            }
+    )
+    ResponseEntity<Void> resignUser(@PathVariable Long userId);
+
+    @Operation(summary = "사용자 상태 변경", description = "사용자의 상태(재직/휴직/퇴사)를 변경하는 PATCH API")
+    @ApiResponses(
+            value = {
+                    @ApiResponse(
+                            responseCode = "200",
+                            description = "상태 변경 성공"
+                    ),
+                    @ApiResponse(
+                            responseCode = "400",
+                            description = "관리자 계정은 퇴사 처리할 수 없습니다.",
+                            content = @Content(schema = @Schema(implementation = ErrorResponse.class))
+                    ),
+                    @ApiResponse(
+                            responseCode = "404",
+                            description = "사용자 정보를 찾을 수 없습니다.",
+                            content = @Content(schema = @Schema(implementation = ErrorResponse.class))
+                    )
+            }
+    )
+    ResponseEntity<Void> updateUserStatus(
+            @PathVariable Long userId,
+            @RequestBody UpdateUserStatusRequest request
+    );
 }
diff --git a/src/main/java/com/bmilab/backend/domain/user/controller/AdminUserController.java b/src/main/java/com/bmilab/backend/domain/user/controller/AdminUserController.java
index 66db8581..068f321e 100644
--- a/src/main/java/com/bmilab/backend/domain/user/controller/AdminUserController.java
+++ b/src/main/java/com/bmilab/backend/domain/user/controller/AdminUserController.java
@@ -2,6 +2,7 @@
 
 import com.bmilab.backend.domain.user.dto.request.RegisterUserRequest;
 import com.bmilab.backend.domain.user.dto.request.AdminUpdateUserRequest;
+import com.bmilab.backend.domain.user.dto.request.UpdateUserStatusRequest;
 import com.bmilab.backend.domain.user.dto.request.UserAccountEmailRequest;
 import com.bmilab.backend.domain.user.dto.response.UserDetail;
 import com.bmilab.backend.domain.user.service.AuthService;
@@ -67,4 +68,21 @@ public ResponseEntity<Void> sendAccountEmail(
         userService.sendAccountEmail(userId, request);
         return ResponseEntity.ok().build();
     }
+
+    @PatchMapping("/{userId}/resign")
+    public ResponseEntity<Void> resignUser(@PathVariable Long userId) {
+
+        userService.resignUser(userId);
+        return ResponseEntity.ok().build();
+    }
+
+    @PatchMapping("/{userId}/status")
+    public ResponseEntity<Void> updateUserStatus(
+            @PathVariable Long userId,
+            @RequestBody @Valid UpdateUserStatusRequest request
+    ) {
+
+        userService.updateUserStatus(userId, request.status());
+        return ResponseEntity.ok().build();
+    }
 }
diff --git a/src/main/java/com/bmilab/backend/domain/user/dto/request/UpdateUserStatusRequest.java b/src/main/java/com/bmilab/backend/domain/user/dto/request/UpdateUserStatusRequest.java
new file mode 100644
index 00000000..59ecb49d
--- /dev/null
+++ b/src/main/java/com/bmilab/backend/domain/user/dto/request/UpdateUserStatusRequest.java
@@ -0,0 +1,12 @@
+package com.bmilab.backend.domain.user.dto.request;
+
+import com.bmilab.backend.domain.user.enums.UserStatus;
+import io.swagger.v3.oas.annotations.media.Schema;
+import jakarta.validation.constraints.NotNull;
+
+public record UpdateUserStatusRequest(
+        @Schema(description = "사용자 상태", example = "RESIGNED")
+        @NotNull(message = "사용자 상태는 필수입니다.")
+        UserStatus status
+) {
+}
\ No newline at end of file
diff --git a/src/main/java/com/bmilab/backend/domain/user/entity/User.java b/src/main/java/com/bmilab/backend/domain/user/entity/User.java
index 58881fc9..a84cb2c4 100644
--- a/src/main/java/com/bmilab/backend/domain/user/entity/User.java
+++ b/src/main/java/com/bmilab/backend/domain/user/entity/User.java
@@ -1,7 +1,9 @@
 package com.bmilab.backend.domain.user.entity;
 
 import com.bmilab.backend.domain.user.enums.UserPosition;
+import com.bmilab.backend.domain.user.enums.UserStatus;
 import com.bmilab.backend.global.entity.BaseTimeEntity;
+import java.time.LocalDateTime;
 import jakarta.persistence.Column;
 import jakarta.persistence.Entity;
 import jakarta.persistence.EnumType;
@@ -52,6 +54,13 @@ public class User extends BaseTimeEntity {
     @Enumerated(EnumType.STRING)
     private Role role;
 
+    @Enumerated(EnumType.STRING)
+    @Column(nullable = false)
+    @Builder.Default
+    private UserStatus status = UserStatus.ACTIVE;
+
+    @Column(name = "resigned_at")
+    private LocalDateTime resignedAt;
 
     public void updatePassword(String newPassword) {
         this.password = newPassword;
@@ -76,4 +85,20 @@ public void updateRole(Role role) {
     public boolean isAdmin() {
         return Role.ADMIN.equals(role);
     }
+
+    public boolean isActive() {
+        return UserStatus.ACTIVE.equals(status);
+    }
+
+    public void resign() {
+        this.status = UserStatus.RESIGNED;
+        this.resignedAt = LocalDateTime.now();
+    }
+
+    public void updateStatus(UserStatus status) {
+        this.status = status;
+        if (status == UserStatus.RESIGNED) {
+            this.resignedAt = LocalDateTime.now();
+        }
+    }
 }
diff --git a/src/main/java/com/bmilab/backend/domain/user/enums/UserStatus.java b/src/main/java/com/bmilab/backend/domain/user/enums/UserStatus.java
new file mode 100644
index 00000000..cf04f9d9
--- /dev/null
+++ b/src/main/java/com/bmilab/backend/domain/user/enums/UserStatus.java
@@ -0,0 +1,14 @@
+package com.bmilab.backend.domain.user.enums;
+
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+
+@Getter
+@AllArgsConstructor
+public enum UserStatus {
+    ACTIVE("재직"),
+    ON_LEAVE("휴직"),
+    RESIGNED("퇴사");
+
+    private final String description;
+}
\ No newline at end of file
diff --git a/src/main/java/com/bmilab/backend/domain/user/exception/UserErrorCode.java b/src/main/java/com/bmilab/backend/domain/user/exception/UserErrorCode.java
index 430d17cb..99255d46 100644
--- a/src/main/java/com/bmilab/backend/domain/user/exception/UserErrorCode.java
+++ b/src/main/java/com/bmilab/backend/domain/user/exception/UserErrorCode.java
@@ -15,6 +15,8 @@ public enum UserErrorCode implements ErrorCode {
     SAME_AS_CURRENT_PASSWORD("새 비밀번호가 현재 비밀번호와 같습니다.", HttpStatus.BAD_REQUEST),
     INVALID_PROFILE_IMAGE_FILE_TYPE("프로필 이미지의 파일 형식이 잘못되었습니다.", HttpStatus.BAD_REQUEST),
     DUPLICATE_EMAIL("이미 가입된 이메일입니다.", HttpStatus.CONFLICT),
+    USER_NOT_ACTIVE("비활성화된 계정입니다.", HttpStatus.FORBIDDEN),
+    CANNOT_RESIGN_ADMIN("관리자 계정은 퇴사 처리할 수 없습니다.", HttpStatus.BAD_REQUEST),
     ;
 
     private final String message;
diff --git a/src/main/java/com/bmilab/backend/domain/user/service/UserService.java b/src/main/java/com/bmilab/backend/domain/user/service/UserService.java
index 885deed7..092818e8 100644
--- a/src/main/java/com/bmilab/backend/domain/user/service/UserService.java
+++ b/src/main/java/com/bmilab/backend/domain/user/service/UserService.java
@@ -19,6 +19,7 @@
 import com.bmilab.backend.domain.user.entity.UserInfo;
 import com.bmilab.backend.domain.user.entity.UserProjectCategory;
 import com.bmilab.backend.domain.user.entity.UserSubAffiliation;
+import com.bmilab.backend.domain.user.enums.UserStatus;
 import com.bmilab.backend.domain.user.event.UserEducationUpdateEvent;
 import com.bmilab.backend.domain.user.exception.UserErrorCode;
 import com.bmilab.backend.domain.user.repository.UserEducationRepository;
@@ -287,6 +288,30 @@ public void deleteUserById(Long userId) {
         userRepository.deleteById(userId);
     }
 
+    @Transactional
+    public void resignUser(Long userId) {
+
+        User user = findUserById(userId);
+
+        if (user.isAdmin()) {
+            throw new ApiException(UserErrorCode.CANNOT_RESIGN_ADMIN);
+        }
+
+        user.resign();
+    }
+
+    @Transactional
+    public void updateUserStatus(Long userId, UserStatus status) {
+
+        User user = findUserById(userId);
+
+        if (user.isAdmin() && status == UserStatus.RESIGNED) {
+            throw new ApiException(UserErrorCode.CANNOT_RESIGN_ADMIN);
+        }
+
+        user.updateStatus(status);
+    }
+
     public SearchUserResponse searchUsers(String keyword) {
 
         List<User> users = userRepository.searchUsersByKeyword(keyword);
diff --git a/src/main/java/com/bmilab/backend/global/security/UserAuthInfoService.java b/src/main/java/com/bmilab/backend/global/security/UserAuthInfoService.java
index 1e4bb71f..e58abb26 100644
--- a/src/main/java/com/bmilab/backend/global/security/UserAuthInfoService.java
+++ b/src/main/java/com/bmilab/backend/global/security/UserAuthInfoService.java
@@ -1,6 +1,7 @@
 package com.bmilab.backend.global.security;
 
 import com.bmilab.backend.domain.user.entity.User;
+import com.bmilab.backend.domain.user.exception.UserErrorCode;
 import com.bmilab.backend.domain.user.repository.UserRepository;
 import com.bmilab.backend.global.exception.ApiException;
 import com.bmilab.backend.global.exception.GlobalErrorCode;
@@ -21,6 +22,10 @@ public UserDetails loadUserByUsername(String email) {
             User user = userRepository.findByEmail(email)
                     .orElseThrow(() -> new ApiException(GlobalErrorCode.SECURITY_USER_NOT_FOUND));
 
+            if (!user.isActive()) {
+                throw new ApiException(UserErrorCode.USER_NOT_ACTIVE);
+            }
+
             return new UserAuthInfo(user, email);
         } catch(UsernameNotFoundException exception) {
             throw new ApiException(GlobalErrorCode.SECURITY_USER_NOT_FOUND, exception);