Rewrite View Header into first views-row I need to rewrite/move the header of one View into the first row of that View. 

Current View output:

&lt;div class="view"&gt;
    &lt;div class="view-header"&gt;view header text&lt;/div&gt;
    &lt;div class="view-content"&gt;
        &lt;div class="views-row views-row-1"&gt;output&lt;/div&gt;
        &lt;div class="views-row views-row-2"&gt;output&lt;/div&gt;
        &lt;div class="views-row views-row-3"&gt;output&lt;/div&gt;
        &lt;div class="views-row views-row-4"&gt;output&lt;/div&gt;
        &lt;div class="views-row views-row-5"&gt;output&lt;/div&gt;
        &lt;div class="views-row views-row-6"&gt;output&lt;/div&gt;
    &lt;/div&gt;
&lt;/div&gt;


Desired Output:

&lt;div class="view"&gt;
    &lt;div class="view-content"&gt;
        &lt;div class="views-row views-row-1"&gt;view header text&lt;/div&gt;
        &lt;div class="views-row views-row-2"&gt;output&lt;/div&gt;
        &lt;div class="views-row views-row-3"&gt;output&lt;/div&gt;
        &lt;div class="views-row views-row-4"&gt;output&lt;/div&gt;
        &lt;div class="views-row views-row-5"&gt;output&lt;/div&gt;
        &lt;div class="views-row views-row-6"&gt;output&lt;/div&gt;
        &lt;div class="views-row views-row-7"&gt;output&lt;/div&gt;
    &lt;/div&gt;
&lt;/div&gt;


How can this be accomplished?

The views-row divs are then displayed inline in a responsive flex grid, so that each views-row div has the same height as its neighbor divs on that same row. Each views-row div is 25% width, so they are displayed in 4 columns (4 divs across the page, with subsequent divs wrapping in 4 additional columns below as needed).

I need the header to be part of that flex grid. I tried applying the flex grid markup to the "view-header" div and the "view-content" div, but it does not provide the desired result.

Thanks!
You can use hook_views_post_execute() or hook_views_pre_render() hooks. Provide you just an example, so you have to add validations and change format of $item variable youself, it depends of your views configuration.

/**
 * Implements hook_views_post_execute().
 */
function mymodule_views_post_execute(&amp;$view) {
  $item = (object) array('node_title' =&gt; $view-&gt;header['area']-&gt;options['content']);
  array_unshift($view-&gt;result, $item);
}