Best way to re-populate input field with Model data on front-end?
The way the Craft docs do it is basically how you are already:

&lt;label for="userLastName"&gt;Last Name *&lt;/label&gt;
&lt;input id="userLastName" type="text" name="fields[userLastName]" {%- if entry is defined %} value="{{ entry.userLastName }}"{% endif -%}&gt;