Hall, 29, joins the Cowboys on a two-year deal after spending just one season in Super League with the Bulls.
He was part of the Manly squad that beat Melbourne in the 2008 Grand Final, before heading to Bradford last season, for whom he played 28 games.
“Signing with the Cowboys is an ideal opportunity for me to better my football and re-join the NRL with a club heading in the right direction that boasts such a big support group,” Hall said.
“It’ll be great to get settled in at the club and take on a bit of a leadership role, especially with a lot of young blokes making their mark this year as well.”
Cowboys Football Manager Peter Parr says Hall will fit in will to the re-modelling of the Cowboys’ squad.
“Glenn will give us a good balance of youth and experience when he comes on board,” Parr said.