diff --git a/src/Umbraco.Core/Events/UnattendedInstallEventArgs.cs b/src/Umbraco.Core/Events/UnattendedInstallEventArgs.cs
new file mode 100644
index 0000000000..3029126dea
--- /dev/null
+++ b/src/Umbraco.Core/Events/UnattendedInstallEventArgs.cs
@@ -0,0 +1,9 @@
+namespace Umbraco.Core.Events
+{
+    /// <summary>
+    /// Used to notify that an Unattended install has completed
+    /// </summary>
+    public class UnattendedInstallEventArgs : System.ComponentModel.CancelEventArgs
+    {
+    }
+}
diff --git a/src/Umbraco.Core/Runtime/CoreRuntime.cs b/src/Umbraco.Core/Runtime/CoreRuntime.cs
index 25bb5d3151..4345469f54 100644
--- a/src/Umbraco.Core/Runtime/CoreRuntime.cs
+++ b/src/Umbraco.Core/Runtime/CoreRuntime.cs
@@ -1,13 +1,17 @@
-using System;
+using Newtonsoft.Json;
+using System;
 using System.Collections.Generic;
 using System.Diagnostics;
+using System.IO;
 using System.Linq;
+using System.Runtime.Serialization;
 using System.Threading;
 using System.Web;
 using System.Web.Hosting;
 using Umbraco.Core.Cache;
 using Umbraco.Core.Composing;
 using Umbraco.Core.Configuration;
+using Umbraco.Core.Events;
 using Umbraco.Core.Exceptions;
 using Umbraco.Core.IO;
 using Umbraco.Core.Logging;
@@ -16,6 +20,9 @@ using Umbraco.Core.Migrations.Install;
 using Umbraco.Core.Migrations.Upgrade;
 using Umbraco.Core.Persistence;
 using Umbraco.Core.Persistence.Mappers;
+using Umbraco.Core.Scoping;
+using Umbraco.Core.Security;
+using Umbraco.Core.Services;
 using Umbraco.Core.Sync;
 
 namespace Umbraco.Core.Runtime
@@ -119,6 +126,9 @@ namespace Umbraco.Core.Runtime
 
             try
             {
+                // Setup event listener
+                UnattendedInstalled += CoreRuntime_UnattendedInstalled;
+
                 // throws if not full-trust
                 new AspNetHostingPermission(AspNetHostingPermissionLevel.Unrestricted).Demand();
 
@@ -162,8 +172,7 @@ namespace Umbraco.Core.Runtime
                 // run handlers
                 RuntimeOptions.DoRuntimeEssentials(composition, appCaches, typeLoader, databaseFactory);
 
-                // determines if unattended install is enabled and performs it if required
-                DoUnattendedInstall(databaseFactory);
+                
 
                 // register runtime-level services
                 // there should be none, really - this is here "just in case"
@@ -190,6 +199,13 @@ namespace Umbraco.Core.Runtime
                 // create the factory
                 _factory = Current.Factory = composition.CreateFactory();
 
+                // determines if unattended install is enabled and performs it if required
+                DoUnattendedInstall(databaseFactory);
+
+                // determine our runtime level (AFTER UNATTENDED INSTALL)
+                // TODO: Feels kinda weird to call this again
+                DetermineRuntimeLevel(databaseFactory, ProfilingLogger);
+
                 // if level is Run and reason is UpgradeMigrations, that means we need to perform an unattended upgrade
                 if (_state.Reason == RuntimeLevelReason.UpgradeMigrations && _state.Level == RuntimeLevel.Run)
                 {
@@ -203,8 +219,6 @@ namespace Umbraco.Core.Runtime
                 // create & initialize the components
                 _components = _factory.GetInstance<ComponentCollection>();
                 _components.Initialize();
-
-
             }
             catch (Exception e)
             {
@@ -242,6 +256,93 @@ namespace Umbraco.Core.Runtime
             return _factory;
         }
 
+        private void CoreRuntime_UnattendedInstalled(IRuntime sender, UnattendedInstallEventArgs e)
+        {
+            var unattendedName = Environment.GetEnvironmentVariable("UnattendedUserName");
+            var unattendedEmail = Environment.GetEnvironmentVariable("UnattendedUserEmail");
+            var unattendedPassword = Environment.GetEnvironmentVariable("UnattendedUserPassword");
+
+            var fileExists = false;
+            var filePath = IOHelper.MapPath("~/App_Data/unattended.user.json");
+
+            // No values store in ENV vars - try fallback file of /app_data/unattended.user.json
+            if (unattendedName.IsNullOrWhiteSpace()
+                || unattendedEmail.IsNullOrWhiteSpace()
+                || unattendedPassword.IsNullOrWhiteSpace())
+            {
+                
+                fileExists = File.Exists(filePath);
+                if (fileExists == false)
+                {
+                    return;
+                }
+
+                // Attempt to deserialize JSON
+                try
+                {
+                    var fileContents = File.ReadAllText(filePath);
+                    var credentials = JsonConvert.DeserializeObject<UnattendedUserConfig>(fileContents);
+
+                    unattendedName = credentials.Name;
+                    unattendedEmail = credentials.Email;
+                    unattendedPassword = credentials.Password;
+                }
+                catch (Exception ex)
+                {
+
+                    throw;
+                }
+            }
+
+            // ENV Variables & JSON still empty
+            if (unattendedName.IsNullOrWhiteSpace()
+                || unattendedEmail.IsNullOrWhiteSpace()
+                || unattendedPassword.IsNullOrWhiteSpace())
+            {
+                return;
+            }
+
+
+            // Update user details
+            var currentProvider = MembershipProviderExtensions.GetUsersMembershipProvider();
+            var admin = Current.Services.UserService.GetUserById(Constants.Security.SuperUserId);
+            if (admin == null)
+            {
+                throw new InvalidOperationException("Could not find the super user!");
+            }
+
+            var membershipUser = currentProvider.GetUser(Constants.Security.SuperUserId, true);
+            if (membershipUser == null)
+            {
+                throw new InvalidOperationException($"No user found in membership provider with id of {Constants.Security.SuperUserId}.");
+            }
+
+            try
+            {
+                var success = membershipUser.ChangePassword("default", unattendedPassword.Trim());
+                if (success == false)
+                {
+                    throw new FormatException("Password must be at least " + currentProvider.MinRequiredPasswordLength + " characters long and contain at least " + currentProvider.MinRequiredNonAlphanumericCharacters + " symbols");
+                }
+            }
+            catch (Exception)
+            {
+                throw new FormatException("Password must be at least " + currentProvider.MinRequiredPasswordLength + " characters long and contain at least " + currentProvider.MinRequiredNonAlphanumericCharacters + " symbols");
+            }
+
+            admin.Email = unattendedEmail.Trim();
+            admin.Name = unattendedName.Trim();
+            admin.Username = unattendedEmail.Trim();
+
+            Current.Services.UserService.Save(admin);
+
+            // Delete JSON file if it existed to tidy 
+            if (fileExists)
+            {
+                File.Delete(filePath);
+            }
+        }
+
         private void DoUnattendedInstall(IUmbracoDatabaseFactory databaseFactory)
         {
             // unattended install is not enabled
@@ -285,6 +386,11 @@ namespace Umbraco.Core.Runtime
                     var creator = new DatabaseSchemaCreator(database, Logger);
                     creator.InitializeDatabaseSchema();
                     database.CompleteTransaction();
+
+                    // Emit an event that unattended install completed
+                    // Then this event can be listened for and create an unattended user
+                    UnattendedInstalled?.Invoke(this, new UnattendedInstallEventArgs());
+
                     Logger.Info<CoreRuntime>("Unattended install completed.");
                 }
                 catch (Exception ex)
@@ -397,6 +503,7 @@ namespace Umbraco.Core.Runtime
         public virtual void Terminate()
         {
             _components?.Terminate();
+            UnattendedInstalled -= CoreRuntime_UnattendedInstalled;
         }
 
         /// <summary>
@@ -404,7 +511,7 @@ namespace Umbraco.Core.Runtime
         /// </summary>
         public virtual void Compose(Composition composition)
         {
-            // nothing
+            // Nothing
         }
 
         #region Getters
@@ -465,5 +572,23 @@ namespace Umbraco.Core.Runtime
         }
 
         #endregion
+
+        /// <summary>
+        /// Event to be used to notify when the Unattended Install has finished
+        /// </summary>
+        public static event TypedEventHandler<IRuntime, UnattendedInstallEventArgs> UnattendedInstalled;
+
+        [DataContract]
+        public class UnattendedUserConfig
+        {
+            [DataMember(Name = "name")]
+            public string Name { get; set; }
+
+            [DataMember(Name = "email")]
+            public string Email { get; set; }
+
+            [DataMember(Name = "password")]
+            public string Password { get; set; }
+        }
     }
 }
diff --git a/src/Umbraco.Core/Umbraco.Core.csproj b/src/Umbraco.Core/Umbraco.Core.csproj
index 0a453ad75f..14444f5d59 100755
--- a/src/Umbraco.Core/Umbraco.Core.csproj
+++ b/src/Umbraco.Core/Umbraco.Core.csproj
@@ -131,6 +131,7 @@
     <Compile Include="Constants-CharArrays.cs" />
     <Compile Include="Collections\EventClearingObservableCollection.cs" />
     <Compile Include="Constants-SqlTemplates.cs" />
+    <Compile Include="Events\UnattendedInstallEventArgs.cs" />
     <Compile Include="Logging\ILogger2.cs" />
     <Compile Include="Logging\Logger2Extensions.cs" />
     <Compile Include="Dashboards\ContentDashboardSettings.cs" />