Same concept, and make the collection_action return HTML markup to reflect the newly sorted items. Requires Nokogiri for parsing the html

activeadmin_sortable.js.coffee

# http://stackoverflow.com/a/8936202
#
# ActiveAdmin already includes the necessary jquery in active_admin/base,
# so just add this to javascripts/active_admin.js after //= require active_admin/base
#
#
# Serialize and Sort
#
# model_name - you guessed it, the name of the model we are calling sort on.
#              This is the actual variable name, no need to change it.
#
sendSortRequestOfModel = (model_name, tbody) ->
  formData = $(tbody).sortable('serialize')
  formData += '&' + $('meta[name=csrf-param]').attr('content') +
    '=' + encodeURIComponent($('meta[name=csrf-token]').attr('content'))
  content = $(tbody).html()

  formData += '&markup=' + encodeURIComponent(content)
  formData += '&utf8=✓'
  $.ajaxSetup({ scriptCharset: "utf-8" ,contentType: "application/x-www-form-urlencoded; charset=UTF-8" })

  $.ajax
    type: 'post'
    data: formData
    dataType: 'html'
    contentType: 'application/x-www-form-urlencoded; charset=UTF-8'
    url: '/admin/' + model_name + '/sort'
    success: (data, textStatus, jqXHR) ->
      $(tbody).html data

enableSort = (model_name, tbody) ->
  $(tbody).disableSelection()
  $(tbody).sortable
    axis: 'y'
    cursor: 'move'
    update: (event, ui) ->
      sendSortRequestOfModel(model_name, tbody)

jQuery ($) ->
  if $('body.admin_profiles.index').length
      enableSort('profiles', '#index_table_profiles tbody')

profile.rb

ActiveAdmin.register Profile do

  permit_params :name, :title, :image, :bio, :quote, :featured, :thumb, :second_col, :display_order

  config.sort_order = "display_order_asc"

  collection_action :sort, :method => :post do
    params[:profile].each_with_index do |id, index|
      Profile.update_all(['display_order=?', index+1], ['id=?', id])
    end

    content = Nokogiri::HTML(params[:markup], nil, 'utf-8')

    rows = content.css('tr')
    counter = 1
    rows.each do |row|
      display_order_col = row.at_css 'td.col-display_order'
      if display_order_col
        display_order_col.content = counter
      end
      row['class'] = counter % 2 == 0 ? 'even' : 'odd'
      counter = counter+1

    end
    render text: content.to_html
  end
  
  ...
  
end