diff --git a/apps/secretary-api/alembic/versions/0017_ticket_requester_tenant_ids.py b/apps/secretary-api/alembic/versions/0017_ticket_requester_tenant_ids.py
new file mode 100644
index 0000000..283d98b
--- /dev/null
+++ b/apps/secretary-api/alembic/versions/0017_ticket_requester_tenant_ids.py
@@ -0,0 +1,43 @@
+"""store all SSO tenant memberships on support tickets"""
+
+from __future__ import annotations
+
+from alembic import op
+from sqlalchemy import inspect
+import sqlalchemy as sa
+
+
+revision = "0017_ticket_requester_tenant_ids"
+down_revision = "0016_feedback_status_stages"
+branch_labels = None
+depends_on = None
+
+
+def upgrade() -> None:
+    bind = op.get_bind()
+    columns = {
+        column["name"]
+        for column in inspect(bind).get_columns("support_tickets")
+    }
+    if "requester_tenant_ids" not in columns:
+        op.add_column(
+            "support_tickets",
+            sa.Column("requester_tenant_ids", sa.JSON(), nullable=True),
+        )
+        op.execute(
+            """
+            UPDATE support_tickets
+            SET requester_tenant_ids = JSON_ARRAY(requester_tenant_id)
+            WHERE requester_tenant_ids IS NULL
+            """
+        )
+
+
+def downgrade() -> None:
+    bind = op.get_bind()
+    columns = {
+        column["name"]
+        for column in inspect(bind).get_columns("support_tickets")
+    }
+    if "requester_tenant_ids" in columns:
+        op.drop_column("support_tickets", "requester_tenant_ids")
diff --git a/apps/secretary-api/app/api/routes/access.py b/apps/secretary-api/app/api/routes/access.py
index e8f067e..e11c998 100644
--- a/apps/secretary-api/app/api/routes/access.py
+++ b/apps/secretary-api/app/api/routes/access.py
@@ -209,6 +209,7 @@ def get_my_access(
     return {
         "user_id": principal.user_id,
         "tenant_id": principal.tenant_id,
+        "tenant_ids": principal.tenant_ids,
         "email": principal.email,
         "name": principal.name,
         "department": principal.department,
diff --git a/apps/secretary-api/app/api/routes/tickets.py b/apps/secretary-api/app/api/routes/tickets.py
index 5e8216f..7a94757 100644
--- a/apps/secretary-api/app/api/routes/tickets.py
+++ b/apps/secretary-api/app/api/routes/tickets.py
@@ -276,6 +276,7 @@ async def create_ticket(
             # because empty values fail min_length validation first.
             requester_id=principal.user_id,
             requester_tenant_id=principal.tenant_id,
+            requester_tenant_ids=principal.tenant_ids,
             requester_contact=str(form.get("requester_contact") or ""),
             title=str(form.get("title") or ""),
             description=str(form.get("description") or ""),
@@ -288,6 +289,7 @@ async def create_ticket(
         request_payload = request_payload.model_copy(update={
             "requester_id": principal.user_id,
             "requester_tenant_id": principal.tenant_id,
+            "requester_tenant_ids": principal.tenant_ids,
             "requester_email": principal.email,
             "requester_name": principal.name,
             "requester_department": principal.department,
@@ -300,6 +302,7 @@ async def create_ticket(
         "workspace_code": workspace_code,
         "requester_id": principal.user_id,
         "requester_tenant_id": principal.tenant_id,
+        "requester_tenant_ids": principal.tenant_ids,
         "requester_email": principal.email,
         "requester_name": principal.name,
         "requester_department": principal.department,
diff --git a/apps/secretary-api/app/db/models.py b/apps/secretary-api/app/db/models.py
index 882dd7a..58bbc12 100644
--- a/apps/secretary-api/app/db/models.py
+++ b/apps/secretary-api/app/db/models.py
@@ -144,6 +144,7 @@ class SupportTicket(Base):
     workspace_id: Mapped[int] = mapped_column(ForeignKey("workspaces.id"))
     requester_id: Mapped[str] = mapped_column(String(100))
     requester_tenant_id: Mapped[str] = mapped_column(String(100))
+    requester_tenant_ids: Mapped[list[str] | None] = mapped_column(JSON, nullable=True)
     requester_contact: Mapped[str | None] = mapped_column(String(100), nullable=True)
     requester_email: Mapped[str | None] = mapped_column(String(320), nullable=True)
     requester_name: Mapped[str | None] = mapped_column(String(100), nullable=True)
@@ -323,4 +324,4 @@ class Attachment(Base):
 
     ticket: Mapped[SupportTicket] = relationship(back_populates="attachments")
     comment: Mapped[TicketComment | None] = relationship(back_populates="attachments")
-    workspace: Mapped[Workspace] = relationship(back_populates="attachments")
\ No newline at end of file
+    workspace: Mapped[Workspace] = relationship(back_populates="attachments")
diff --git a/apps/secretary-api/app/schemas/ticket.py b/apps/secretary-api/app/schemas/ticket.py
index d811336..7413995 100644
--- a/apps/secretary-api/app/schemas/ticket.py
+++ b/apps/secretary-api/app/schemas/ticket.py
@@ -7,6 +7,7 @@ class TicketCreateRequest(BaseModel):
     workspace_code: str = Field(default="", max_length=50)
     requester_id: str = Field(..., min_length=1, max_length=100)
     requester_tenant_id: str = Field(..., min_length=1, max_length=100)
+    requester_tenant_ids: list[str] = Field(default_factory=list)
     requester_contact: str | None = Field(default=None, max_length=100)
     requester_email: str | None = Field(default=None, max_length=320)
     requester_name: str | None = Field(default=None, max_length=100)
@@ -187,6 +188,7 @@ class SupportTicketRecord(BaseModel):
     description: str
     requester_id: str
     requester_tenant_id: str
+    requester_tenant_ids: list[str] = Field(default_factory=list)
     requester_contact: str
     requester_email: str | None
     requester_name: str | None
diff --git a/apps/secretary-api/app/services/ticket_service.py b/apps/secretary-api/app/services/ticket_service.py
index 4d05740..892778b 100644
--- a/apps/secretary-api/app/services/ticket_service.py
+++ b/apps/secretary-api/app/services/ticket_service.py
@@ -169,6 +169,7 @@ class TicketService:
             workspace_id=workspace.id,
             requester_id=payload.requester_id,
             requester_tenant_id=payload.requester_tenant_id,
+            requester_tenant_ids=payload.requester_tenant_ids or [payload.requester_tenant_id],
             requester_contact=payload.requester_contact or "",
             requester_email=payload.requester_email,
             requester_name=payload.requester_name,
@@ -1301,6 +1302,7 @@ class TicketService:
             description=ticket.description,
             requester_id=ticket.requester_id,
             requester_tenant_id=ticket.requester_tenant_id,
+            requester_tenant_ids=ticket.requester_tenant_ids or [ticket.requester_tenant_id],
             requester_contact=ticket.requester_contact or "",
             requester_email=requester_email,
             requester_name=requester_name,
diff --git a/apps/web/src/pages/api/support/workspaces/[workspaceCode]/submit.ts b/apps/web/src/pages/api/support/workspaces/[workspaceCode]/submit.ts
index d5e5795..8a2bf83 100644
--- a/apps/web/src/pages/api/support/workspaces/[workspaceCode]/submit.ts
+++ b/apps/web/src/pages/api/support/workspaces/[workspaceCode]/submit.ts
@@ -67,6 +67,30 @@ const getSsoRequesterFields = (claims: Record<string, unknown>) => {
     (ancestor) => getStringValue(ancestor.type) === 'COMPANY',
   );
 
+  const tenantIds = new Set<string>();
+  const addTenantId = (value: unknown) => {
+    if (typeof value === 'string' && value.trim()) tenantIds.add(value.trim());
+  };
+  for (const source of tokenSources) {
+    const directTenantIds = source.tenant_ids ?? source.tenantIds;
+    if (Array.isArray(directTenantIds)) {
+      directTenantIds.forEach(addTenantId);
+    }
+    addTenantId(source.tenant_id);
+    addTenantId(source.tenantId);
+    addTenantId(asRecord(source.tenant)?.id);
+    if (Array.isArray(source.joinedTenants)) {
+      source.joinedTenants.forEach((tenant) => addTenantId(asRecord(tenant)?.id));
+    }
+    if (Array.isArray(source.tenants)) {
+      source.tenants.forEach((tenant) => addTenantId(asRecord(tenant)?.id));
+    } else if (source.tenants && typeof source.tenants === 'object') {
+      Object.values(source.tenants as Record<string, unknown>).forEach((tenant) =>
+        addTenantId(asRecord(tenant)?.id),
+      );
+    }
+  }
+
   return {
     requester_id: readClaim('sub', 'user_id', 'id'),
     requester_uuid: readClaim('sub', 'user_id', 'id'),
@@ -89,6 +113,7 @@ const getSsoRequesterFields = (claims: Record<string, unknown>) => {
       'employee_number',
       'employeeNumber',
     ),
+    requester_tenant_ids: JSON.stringify([...tenantIds]),
   };
 };
 const MAX_ATTACHMENT_COUNT = 10;
diff --git a/apps/web/src/server/local-sso.ts b/apps/web/src/server/local-sso.ts
index 4c40f6a..7df0408 100644
--- a/apps/web/src/server/local-sso.ts
+++ b/apps/web/src/server/local-sso.ts
@@ -46,6 +46,7 @@ interface SsoOrgMember {
   grade?: unknown;
   position?: unknown;
   jobTitle?: unknown;
+  tenant_ids?: string[];
 }
 
 type SsoValueShape =
@@ -220,14 +221,25 @@ const getSsoOrgMember = async (
     tree?: { members?: unknown };
     tenants?: unknown;
   };
+  const tenantIds = new Set<string>();
+  const rawTenants = Array.isArray(data.tenants) ?
+    data.tenants
+  : data.tenants && typeof data.tenants === 'object' ?
+    Object.values(data.tenants as Record<string, unknown>)
+  : [];
+  const tenantRecords = rawTenants
+    .map((tenant) => asRecord(tenant))
+    .filter((tenant): tenant is Record<string, unknown> => tenant !== null);
+  for (const tenant of tenantRecords) {
+    const id = asString(tenant.id) ?? asString(tenant.tenant_id);
+    if (id) tenantIds.add(id);
+  }
+  if (tenantId) tenantIds.add(tenantId);
   const members: Record<string, unknown>[] = [];
   const treeMembers = Array.isArray(data.tree?.members) ? data.tree.members : [];
-  const tenantMembers = Array.isArray(data.tenants) ?
-    data.tenants.flatMap((tenant) => {
-      const record = asRecord(tenant);
-      return Array.isArray(record?.members) ? record.members : [];
-    })
-  : [];
+  const tenantMembers = tenantRecords.flatMap((tenant) =>
+    Array.isArray(tenant.members) ? tenant.members : [],
+  );
 
   for (const candidate of [...treeMembers, ...tenantMembers]) {
     const member = asRecord(candidate);
@@ -236,13 +248,14 @@ const getSsoOrgMember = async (
 
   const subject = asString(info.id) ?? asString(info.sub) ?? asString(info.user_id);
   const email = asString(info.email);
-  return (
-    members.find((member) => {
+  const matchedMember = members.find((member) => {
       const memberId = asString(member.id);
       const memberEmail = asString(member.email);
       return (subject && memberId === subject) || (email && memberEmail === email);
-    }) ?? null
-  );
+    });
+  return matchedMember || tenantIds.size > 0 ?
+      { ...(matchedMember ?? {}), tenant_ids: [...tenantIds] }
+    : null;
 };
 
 const enrichSsoUserInfo = async (accessToken: string, info: OidcUserInfo) => {
@@ -258,6 +271,12 @@ const enrichSsoUserInfo = async (accessToken: string, info: OidcUserInfo) => {
     grade: asString(info.grade) ?? asString(member.grade),
     position: asString(info.position) ?? asString(member.position),
     jobTitle: asString(info.jobTitle) ?? asString(member.jobTitle),
+    tenant_ids: [
+      ...new Set([
+        ...asStringArray(info.tenant_ids ?? info.tenantIds),
+        ...(member.tenant_ids ?? []),
+      ]),
+    ],
   };
 };
 
@@ -539,15 +558,33 @@ const createSupportSession = (info: OidcUserInfo) => {
       'SSO 사용자 정보에 sub 또는 tenant_id가 없습니다. SUPPORT_TENANT_ID를 확인하세요.',
     );
   }
-  const tenantIds = asStringArray(info.tenant_ids ?? info.tenantIds);
-  if (!tenantIds.includes(tenantId)) tenantIds.unshift(tenantId);
+  const tenantIds = new Set(asStringArray(info.tenant_ids ?? info.tenantIds));
+  const addTenantId = (value: unknown) => {
+    const id = asString(value);
+    if (id) tenantIds.add(id);
+  };
+
+  addTenantId(info.tenant_id);
+  addTenantId(info.tenantId);
+  addTenantId(asRecord(info.tenant)?.id);
+  for (const tenant of Array.isArray(info.joinedTenants) ? info.joinedTenants : []) {
+    addTenantId(asRecord(tenant)?.id);
+  }
+  if (Array.isArray(info.tenants)) {
+    for (const tenant of info.tenants) addTenantId(asRecord(tenant)?.id);
+  } else if (info.tenants && typeof info.tenants === 'object') {
+    for (const tenant of Object.values(info.tenants as Record<string, unknown>)) {
+      addTenantId(asRecord(tenant)?.id);
+    }
+  }
+  tenantIds.add(tenantId);
   const now = Math.floor(Date.now() / 1000);
   return signHs256(
     {
       sub: subject,
       sso_sub: subject,
       tenant_id: tenantId,
-      tenant_ids: tenantIds,
+      tenant_ids: [...tenantIds],
       email: asString(info.email),
       name: asString(info.name),
       department: asString(info.department),
diff --git a/apps/web/src/server/support-auth.ts b/apps/web/src/server/support-auth.ts
index 1374b82..cc7ef9d 100644
--- a/apps/web/src/server/support-auth.ts
+++ b/apps/web/src/server/support-auth.ts
@@ -24,6 +24,7 @@ const SSO_TOKEN_CLAIMS_COOKIE_COUNT = `${SSO_TOKEN_CLAIMS_COOKIE}_count`;
 export interface SupportPrincipal {
   user_id: string;
   tenant_id: string;
+  tenant_ids?: string[];
   email?: string | null;
   name?: string | null;
   department?: string | null;
diff --git a/apps/web/src/server/support-types.ts b/apps/web/src/server/support-types.ts
index 3cf50c4..7a6ae8f 100644
--- a/apps/web/src/server/support-types.ts
+++ b/apps/web/src/server/support-types.ts
@@ -87,6 +87,7 @@ export interface SupportTicketRecord extends SupportFeedbackAutomationMetadata {
   description: string;
   requester_id: string;
   requester_tenant_id: string;
+  requester_tenant_ids?: string[];
   requester_contact: string;
   requester_email?: string | null;
   requester_name?: string | null;