Change the color of the message UIAlertController in Swift

You can use attributedStrings to create the color, font, size, and style that you want, and then set the string as the title.

EDIT: Updated with example

let attributedString = NSAttributedString(string: "Invalid Name", attributes: [
  NSParagraphStyleAttributeName: paragraphStyle,
  NSFontAttributeName : UIFont.systemFontOfSize(15),
  NSForegroundColorAttributeName : UIColor.redColor()
])
let alert = UIAlertController(title: "Title", message: "", preferredStyle: .Alert)

alert.setValue(attributedString, forKey: "attributedMessage")

let cancelAction = UIAlertAction(title: "Cancel",
    style: .Default) { (action: UIAlertAction!) -> Void in
}

presentViewController(alert,
    animated: true,
    completion: nil)

Swift 5

    let messageString  = "The message to display"
    var myMutableString = NSMutableAttributedString()
    myMutableString = NSMutableAttributedString(string: messageString as String, attributes: [NSAttributedString.Key.font:UIFont(name: "Poppins-medium", size: 14.0)!])
    myMutableString.addAttribute(NSAttributedString.Key.foregroundColor, value: UIColor.blue, range: NSRange(location:0,length:messageString.count))
    alert.setValue(myMutableString, forKey: "attributedMessage")