Display the first category before the content wrap in Genesis for a single post.

single.php

<?php

add_action( 'genesis_before_content_sidebar_wrap', 'single_display_category_title' );
/**
 * Callback for Genesis 'genesis_before_content_sidebar_wrap' action.
 * 
 * @package Genesis
 * @category Post Template
 * @author Ryan Meier http://www.rfmeier.net
 * 
 * @global object $post The current post within the loop.
 * @return none exit function
 */
function display_category_title(){
  
	// scope in the current post object
	global $post;
	
	// get all the categories for the post
	$categories = get_the_category( $post->ID );
	
	// if invalid categories, return
	if( empty( $categories ) )
		return;
	
	// get the 0th category in the array
	$category = array_shift( $categories );
	
	// display the title
	printf( '<h1 class="category-title">%s</h1>', esc_html( $category->name ) );
	
}