Hayes held the position of Returning Officer for the Labor Caucus, in which he oversaw elections, including the 2013 leadership spill/ballot in June.
At the 2005 Werriwa by-election Hayes polled 55.54 percent of the primary vote, a 2.90-point increase from the October 2004 election.
[1] Hayes, a practising Roman Catholic, was one of the few Labor MPs to publicly oppose the legislation of same-sex marriage.
In October 2020, in the Federation Chamber of the Australian Parliament, while reading out a letter from his cousin who had suffered child abuse, Hayes grabbed at his heart and collapsed.
Later, in the House of Representatives, Labor leader Anthony Albanese and Prime Minister Scott Morrison expressed their wishes for Hayes' speedy recovery.