@ekohl suggested using the pulpcore shell to make the change in this topic: Pulp3 content migration - pulpcore admin is_superuser
# PULP_SETTINGS=/etc/pulp/settings.py pulpcore-manager shell
from django.contrib.auth import get_user_model
user_model = get_user_model()
user = user_model.objects.get(username='admin')
user.is_superuser = True
user.save()