Using the template_include function included in WordPress, paste this code in your child themes functions.php file and modify accordingly.
add_filter( 'template_include', 'front_page_landing_template', 99 );
function front_page_landing_template( $template ) {
if ( is_front_page() ) {
$new_template = locate_template( array( 'page_landing.php' ) );
if ( '' != $new_template ) {
return $new_template ;
}
}
return $template;
}The function only works with page templates and doesn’t work for archive or other template files.
Update: Do NOT use template_redirect to include templates
You could also use a template_redirect in your functions file which returns the same result but this is NOT the best way to include templates so DON’T use this code below.
function landing_page_redirect(){
if( is_front_page() ) {
include( get_stylesheet_directory() . '/page_landing.php' );
exit();
}
}
add_action( 'template_redirect', 'landing_page_redirect' );