diff --git a/apps/bff/src/integrations/salesforce/services/salesforce-account.service.ts b/apps/bff/src/integrations/salesforce/services/salesforce-account.service.ts
index cc2bb1ae..1a445f7b 100644
--- a/apps/bff/src/integrations/salesforce/services/salesforce-account.service.ts
+++ b/apps/bff/src/integrations/salesforce/services/salesforce-account.service.ts
@@ -177,7 +177,7 @@ export class SalesforceAccountService {
 
     const accountPayload: Record<string, unknown> = {
       Name: `${data.firstName} ${data.lastName}`,
-      Phone: data.phone,
+      // Phone is stored on Contact, not Account
       // Portal tracking fields
       [this.portalStatusField]: "Active",
       [this.portalSourceField]: "Portal Checkout",
@@ -236,12 +236,24 @@ export class SalesforceAccountService {
       email: data.email,
     });
 
+    // Map gender values to Salesforce picklist values
+    const mapGenderToSalesforce = (gender: "male" | "female" | "other"): string => {
+      const mapping: Record<"male" | "female" | "other", string> = {
+        male: "男性",
+        female: "女性",
+        other: "Other",
+      };
+      return mapping[gender];
+    };
+
     const contactPayload: Record<string, unknown> = {
       AccountId: data.accountId,
       FirstName: data.firstName,
       LastName: data.lastName,
       Email: data.email,
-      Phone: data.phone,
+      MobilePhone: data.phone,
+      Sex__c: mapGenderToSalesforce(data.gender),
+      Birthdate: data.dateOfBirth, // Salesforce expects YYYY-MM-DD format
     };
 
     try {
@@ -350,4 +362,6 @@ export interface CreateSalesforceContactRequest {
   lastName: string;
   email: string;
   phone: string;
+  gender: "male" | "female" | "other";
+  dateOfBirth: string; // YYYY-MM-DD format
 }
diff --git a/apps/bff/src/modules/auth/infra/workflows/signup-workflow.service.ts b/apps/bff/src/modules/auth/infra/workflows/signup-workflow.service.ts
index 6bbc9d5f..0221a916 100644
--- a/apps/bff/src/modules/auth/infra/workflows/signup-workflow.service.ts
+++ b/apps/bff/src/modules/auth/infra/workflows/signup-workflow.service.ts
@@ -35,7 +35,7 @@ import {
  *
  * Orchestrates the signup process by coordinating:
  * - SignupValidationService: Validates customer numbers and preflight checks
- * - SignupAccountResolverService: Resolves Salesforce accounts
+ * - SalesforceAccountService: Creates new Salesforce accounts and contacts
  * - SignupWhmcsService: Creates WHMCS clients
  * - SignupUserCreationService: Creates portal users with ID mappings
  */
@@ -210,38 +210,16 @@ export class SignupWorkflowService {
   }
 
   /**
-   * Resolve Salesforce account for signup
-   * Either finds existing account by customer number or creates new one
+   * Create a new Salesforce account for signup
+   * Always creates a new account - no lookup by customer number
    */
   private async resolveSalesforceAccount(signupData: SignupRequest): Promise<{
     accountSnapshot: SignupAccountSnapshot;
     customerNumberForWhmcs: string | null;
   }> {
-    const { email, firstName, lastName, phone, address, sfNumber } = signupData;
-    const normalizedCustomerNumber = this.accountResolver.normalizeCustomerNumber(sfNumber);
+    const { email, firstName, lastName, phone, address, gender, dateOfBirth } = signupData;
 
-    if (normalizedCustomerNumber) {
-      // Existing customer - find account by customer number
-      const resolved = await this.accountResolver.getAccountSnapshot(normalizedCustomerNumber);
-      if (!resolved) {
-        throw new BadRequestException(
-          `Salesforce account not found for Customer Number: ${normalizedCustomerNumber}`
-        );
-      }
-
-      if (resolved.WH_Account__c && resolved.WH_Account__c.trim() !== "") {
-        throw new ConflictException(
-          "You already have an account. Please use the login page to access your existing account."
-        );
-      }
-
-      return {
-        accountSnapshot: resolved,
-        customerNumberForWhmcs: normalizedCustomerNumber,
-      };
-    }
-
-    // New customer - create Salesforce account
+    // Check if account already exists by email
     const normalizedEmail = email.toLowerCase().trim();
     const existingAccount = await this.salesforceAccountService.findByEmail(normalizedEmail);
     if (existingAccount) {
@@ -266,6 +244,15 @@ export class SignupWorkflowService {
       throw new BadRequestException("Phone number is required for account creation");
     }
 
+    if (!gender) {
+      throw new BadRequestException("Gender is required for account creation");
+    }
+
+    if (!dateOfBirth) {
+      throw new BadRequestException("Date of birth is required for account creation");
+    }
+
+    // Create new Salesforce account
     const created = await this.salesforceAccountService.createAccount({
       firstName,
       lastName,
@@ -280,6 +267,8 @@ export class SignupWorkflowService {
       lastName,
       email: normalizedEmail,
       phone,
+      gender,
+      dateOfBirth,
       // Address not added to Salesforce during signup
     });
 
diff --git a/apps/bff/src/modules/auth/infra/workflows/signup/signup-account-resolver.service.ts b/apps/bff/src/modules/auth/infra/workflows/signup/signup-account-resolver.service.ts
index 09e8f6b8..093fd5e5 100644
--- a/apps/bff/src/modules/auth/infra/workflows/signup/signup-account-resolver.service.ts
+++ b/apps/bff/src/modules/auth/infra/workflows/signup/signup-account-resolver.service.ts
@@ -28,7 +28,8 @@ export class SignupAccountResolverService {
   async resolveOrCreate(
     signupData: SignupRequest
   ): Promise<{ snapshot: SignupAccountSnapshot; customerNumber: string | null }> {
-    const { sfNumber, email, firstName, lastName, phone, address } = signupData;
+    const { sfNumber, email, firstName, lastName, phone, address, gender, dateOfBirth } =
+      signupData;
     const normalizedCustomerNumber = this.normalizeCustomerNumber(sfNumber);
 
     if (normalizedCustomerNumber) {
@@ -73,6 +74,14 @@ export class SignupAccountResolverService {
       throw new BadRequestException("Phone number is required for account creation");
     }
 
+    if (!gender) {
+      throw new BadRequestException("Gender is required for account creation");
+    }
+
+    if (!dateOfBirth) {
+      throw new BadRequestException("Date of birth is required for account creation");
+    }
+
     const created = await this.salesforceAccountService.createAccount({
       firstName,
       lastName,
@@ -86,6 +95,8 @@ export class SignupAccountResolverService {
       lastName,
       email: normalizedEmail,
       phone,
+      gender,
+      dateOfBirth,
     });
 
     const snapshot: SignupAccountSnapshot = {
diff --git a/packages/domain/customer/contract.ts b/packages/domain/customer/contract.ts
index a3503601..1216f659 100644
--- a/packages/domain/customer/contract.ts
+++ b/packages/domain/customer/contract.ts
@@ -42,6 +42,23 @@ export interface SalesforceAccountRecord {
   [key: string]: unknown;
 }
 
+/**
+ * Salesforce contact record structure
+ * Raw structure from Salesforce API
+ */
+export interface SalesforceContactRecord {
+  Id: string;
+  AccountId?: string | null;
+  FirstName?: string | null;
+  LastName?: string | null;
+  Email?: string | null;
+  MobilePhone?: string | null;
+  Phone?: string | null;
+  Sex__c?: string | null;
+  Birthdate?: string | null; // YYYY-MM-DD format
+  [key: string]: unknown;
+}
+
 // ============================================================================
 // Re-export Types from Schema (Schema-First Approach)
 // ============================================================================
diff --git a/packages/domain/customer/providers/index.ts b/packages/domain/customer/providers/index.ts
index 8d66b4a1..ed015f22 100644
--- a/packages/domain/customer/providers/index.ts
+++ b/packages/domain/customer/providers/index.ts
@@ -10,7 +10,11 @@ export * from "./portal/index.js";
 export * from "./whmcs/index.js";
 
 // Provider-specific integration types (BFF-only convenience re-exports)
-export type { SalesforceAccountFieldMap, SalesforceAccountRecord } from "../contract.js";
+export type {
+  SalesforceAccountFieldMap,
+  SalesforceAccountRecord,
+  SalesforceContactRecord,
+} from "../contract.js";
 export type {
   WhmcsAddClientParams,
   WhmcsValidateLoginParams,