The midfielder, 24, signed for the Gulls on a free transfer on Monday after being released by United manager Alan Knill at the end of last season.
He has been part of two Iron sides that won promotion from League One - as champions in 2007 and via the play-offs two years later - and helped Chesterfield to the League Two title last season while on loan at the B2net Stadium.
"My agent has been doing a lot of work behind the scenes and Hereford asked me to go on trial with them, so I could start my pre-season training," Morris told Torquay's official website.
"We then had interest from Torquay and it seemed like the right thing to do. The club was pushing for promotion last year and that is what I'm looking to do.
"I've actually had three promotions in six years, so I'm looking to keep that nice habit. Hopefully, the club can go one better than last year."