In 2014, Macdonald unsuccessfully campaigned on Twitter to be named the new host of "The Late Late Show" after then-host Craig Ferguson announced he would be leaving. On May 15, 2015, Macdonald was the final stand-up act on the "Late Show with David Letterman": during his set, which ended with him breaking into tears as he told Letterman that he truly loved him, Macdonald included a joke Letterman had told the first time Macdonald had ever seen him, during a 1970s appearance on the Canadian talk show "90 Minutes Live", where a 13-year-old Macdonald had been in the studio audience. Also in 2015, Macdonald was a judge for the ninth season of NBC's "Last Comic Standing", joining the previous season's judges, Roseanne Barr and Keenan Ivory Wayans and replacing fellow Canadian Russell Peters from 2014.