diff --git a/bookwyrm/forms.py b/bookwyrm/forms.py
index 564ea91b2..b96e152f0 100644
--- a/bookwyrm/forms.py
+++ b/bookwyrm/forms.py
@@ -54,6 +54,15 @@ class RegisterForm(CustomForm):
         help_texts = {f: None for f in fields}
         widgets = {"password": PasswordInput()}
 
+    def clean(self):
+        """Check if the username is taken"""
+        cleaned_data = super().clean()
+        localname = cleaned_data.get("localname").strip()
+        if models.User.objects.filter(localname=localname).first():
+            self.add_error(
+                "localname", _("User with this username already exists")
+            )
+
 
 class RatingForm(CustomForm):
     class Meta:
diff --git a/bookwyrm/templates/setup/admin.html b/bookwyrm/templates/setup/admin.html
index 8bba55a8d..ecc84c7e5 100644
--- a/bookwyrm/templates/setup/admin.html
+++ b/bookwyrm/templates/setup/admin.html
@@ -13,7 +13,7 @@
     <div class="column is-half">
         <div class="box has-background-primary-light">
             <h2 class="title is-4">{% trans "Create your account" %}</h2>
-            <form name="register" method="post" action="/register">
+            <form name="register" method="post" action="{% url 'setup' %}">
                 <div class="field">
                     <label class="label" for="id_admin_key">
                         {% trans "Admin key:" %}
diff --git a/bookwyrm/views/landing/register.py b/bookwyrm/views/landing/register.py
index d4d719576..86cd96ea9 100644
--- a/bookwyrm/views/landing/register.py
+++ b/bookwyrm/views/landing/register.py
@@ -42,9 +42,16 @@ class Register(View):
             invite = None
 
         form = forms.RegisterForm(request.POST)
-        errors = False
         if not form.is_valid():
-            errors = True
+            data = {
+                "login_form": forms.LoginForm(),
+                "register_form": form,
+                "invite": invite,
+                "valid": invite.valid() if invite else True,
+            }
+            if invite:
+                return TemplateResponse(request, "landing/invite.html", data)
+            return TemplateResponse(request, "landing/login.html", data)
 
         localname = form.data["localname"].strip()
         email = form.data["email"]
@@ -56,22 +63,6 @@ class Register(View):
             # treat this like a successful registration, but don't do anything
             return redirect("confirm-email")
 
-        # check localname and email uniqueness
-        if models.User.objects.filter(localname=localname).first():
-            form.errors["localname"] = ["User with this username already exists"]
-            errors = True
-
-        if errors:
-            data = {
-                "login_form": forms.LoginForm(),
-                "register_form": form,
-                "invite": invite,
-                "valid": invite.valid() if invite else True,
-            }
-            if invite:
-                return TemplateResponse(request, "landing/invite.html", data)
-            return TemplateResponse(request, "landing/login.html", data)
-
         username = f"{localname}@{DOMAIN}"
         user = models.User.objects.create_user(
             username,
diff --git a/bookwyrm/views/setup.py b/bookwyrm/views/setup.py
index d370c2f00..2d70a7172 100644
--- a/bookwyrm/views/setup.py
+++ b/bookwyrm/views/setup.py
@@ -1,9 +1,14 @@
 """ Installation wizard 🧙 """
+from django.contrib.auth import login
+from django.contrib.auth.models import Group
 from django.core.exceptions import PermissionDenied
+from django.db import transaction
+from django.shortcuts import redirect
 from django.template.response import TemplateResponse
 from django.views import View
 
 from bookwyrm import forms, models
+from bookwyrm.settings import DOMAIN
 
 
 # pylint: disable= no-self-use
@@ -11,8 +16,8 @@ class CreateAdmin(View):
     """manage things like the instance name"""
 
     def get(self, request):
-        """Create admin user"""
-        # only allow this view when an instance is being installed
+        """Create admin user form"""
+        # only allow this view when an instance is being configured
         site = models.SiteSettings.objects.get()
         if not site.install_mode:
             raise PermissionDenied()
@@ -21,3 +26,40 @@ class CreateAdmin(View):
             "register_form": forms.RegisterForm()
         }
         return TemplateResponse(request, "setup/admin.html", data)
+
+    @transaction.atomic
+    def post(self, request):
+        """Create that user"""
+        site = models.SiteSettings.get()
+        # you can't create an admin user if you're in config mode
+        if not site.install_mode:
+            raise PermissionDenied()
+
+        form = forms.RegisterForm(request.POST)
+        if not form.is_valid():
+            data = {"register_form": form}
+            return TemplateResponse(request, "setup/admin.html", data)
+
+        localname = form.data["localname"].strip()
+        username = f"{localname}@{DOMAIN}"
+
+        user = models.User.objects.create_superuser(
+            username,
+            form.data["email"],
+            form.data["password"],
+            localname=localname,
+            local=True,
+            deactivation_reason=None,
+            is_active=True,
+        )
+        # Set "admin" role
+        try:
+            user.groups.set(Group.objects.filter(name__in=["admin", "moderator"]))
+        except Group.DoesNotExist:
+            # this should only happen in tests
+            pass
+
+        login(request, user)
+        site.install_mode = False
+        site.save()
+        return redirect("settings-site")