Office 365: Add accounts into the Site collection administrators list via PowerShell and CSOM

To add accounts (group or User) into the SPO SIte collection admin via code, there are 2 possible solutions:

Via PowerShell and SPO Admin

Really simple case ideal for one shot action, you need to know the exact User/group ID of the SPO account:

Set-SPOUser -Site https://tenant.sharepoint.com/sites/MyCollection -IsSiteCollectionAdmin $true –LoginName “c:0-.f|rolemanager|s-1-1-11-11111111-111111-111111-1111”

Via PowerShell and CSOM

This script is more generic and can be added into a provisionning script you will have to use for your own needs:

[string]$username = "AdminAccount@tenant.onmicrosoft.com" 
[string]$PwdTXTPath = "D:\ExportedPWD-$($username).txt" 
[string]$SPOSiteCollectionURLToSet = https://tenant.sharepoint.com/sites/MyCollection

#c:0-.f|rolemanager|s-1-1-11-11111111-111111-111111-1111 - Company Administrator 
[string]$CompanyAdministratorLogin = "c:0-.f|rolemanager|s-1-1-11-11111111-111111-111111-1111"

# c:0-.f|rolemanager|s-1-1-11-11111111-111111-111111-22222- SharePoint Service Administrator 
[string]$SharePointServiceAdministratorLogin = "c:0-.f|rolemanager|s-1-1-11-11111111-111111-111111-22222"

function Load-DLLandAssemblies 
{ 
    [string]$defaultDLLPath = ""

    # Load assemblies to PowerShell session

    $defaultDLLPath = "C:\Program Files\SharePoint Online Management Shell\Microsoft.Online.SharePoint.PowerShell\Microsoft.SharePoint.Client.dll" 
    [System.Reflection.Assembly]::LoadFile($defaultDLLPath)

    $defaultDLLPath = "C:\Program Files\SharePoint Online Management Shell\Microsoft.Online.SharePoint.PowerShell\Microsoft.SharePoint.Client.Runtime.dll"
    [System.Reflection.Assembly]::LoadFile($defaultDLLPath)

    $defaultDLLPath = "C:\Program Files\SharePoint Online Management Shell\Microsoft.Online.SharePoint.PowerShell\Microsoft.Online.SharePoint.Client.Tenant.dll"
    [System.Reflection.Assembly]::LoadFile($defaultDLLPath) 
}


Function Add-Group-In-SiteCollectionAdmin() 
{ 
    Param( 
        [Parameter(Mandatory=$true,Position=1)][Microsoft.SharePoint.Client.ClientContext]$Context, 
        [Parameter(Mandatory=$true,Position=2)][string]$SPUserOrGroupLogin 
    ) 
    Write-Host " ---------------------------------------------------------"

    $MyspUser = $Context.Web.EnsureUser($SPUserOrGroupLogin); 
    $MyspUser.IsSiteAdmin = $true; 
    $MyspUser.Update() 
    $Context.Load($MyspUser) 
    #send the request containing all operations to the server 
    try{ 
        $context.executeQuery() 
        write-host " >>> info: User or Group Name added in Site Collection admin: [$($MyspUser.Title)]" -foregroundcolor green 
    } 
    catch{ 
        write-host "info: $($_.Exception.Message)" -foregroundcolor red 
    }

    Write-Host " ---------------------------------------------------------" 
}

function SetGroupAsAdministrator([string]$MyRootWebURL) 
{ 
    [bool]$CreateSGSDocLibList = $false 
    
    $Myctx = New-Object Microsoft.SharePoint.Client.ClientContext($MyRootWebURL) 
    $secureStringPwd = ConvertTo-SecureString -string (Get-Content $PwdTXTPath) 
    $creds = New-Object System.Management.Automation.PSCredential -ArgumentList $username, $secureStringPwd 
    $Myctx.Credentials = New-Object Microsoft.SharePoint.Client.SharePointOnlineCredentials($creds.UserName,$creds.Password)
    $Myctx.RequestTimeout = 1000000 # milliseconds 
    $MyspoRootweb = $Myctx.Web 
    $Myctx.Load($MyspoRootweb) 
    $Myctx.ExecuteQuery()

Write-Host " " 
Write-Host " ---------------------------------------------------------" 
Write-Host "  >>>> # Server Version:" $Myctx.ServerVersion " # <<<<<<" -ForegroundColor Green 
Write-Host " ---------------------------------------------------------" 
Write-Host " "

    Add-Group-In-SiteCollectionAdmin -Context $Myctx -SPUserOrGroupLogin $CompanyAdministratorLogin 
    Add-Group-In-SiteCollectionAdmin -Context $Myctx -SPUserOrGroupLogin $SharePointServiceAdministratorLogin

} 
cls 
Load-DLLandAssemblies

SetGroupAsAdministrator $SPOSiteCollectionURLToSet

Fabrice Romelard [MVP]

Original article (in French):

• Office 365: Ajouter un utilisateur ou groupe dans la liste des Site collection Administrator d’un site SharePoint Online via PowerShell et CSOM

Associated WebPages:

• http://sharepoint.stackexchange.com/questions/114421/can-i-use-set-spouser-to-set-an-o365-security-group-as-a-secondary-site-collecti
• https://blogs.msdn.microsoft.com/mimorr/2014/01/22/adding-site-collection-admin-in-csom-in-a-sharepoint-2013-app/