Origin custom loop. One content, rest excerpt.

<?php $i = 1; ?>
.
.
.

<?php if ( $i == 1 ) { ?>

                            <div class="entry-content">

                                <?php the_content( __( 'Continue reading <span class="meta-nav">&rarr;</span>', 'origin' ) ); ?>

                                <?php wp_link_pages( array( 'before' => '<p class="page-links">' . __( 'Pages:', 'origin' ), 'after' => '</p>' ) ); ?>

                            </div><!-- .entry-content -->

                            <?php } else { ?>

                                <div class="entry-summary">
                                    <?php the_excerpt(); ?>
                                </div>

                            <?php } ?>
<?php $i++; ?>