The 26-year-old ended a five-year association with recently-relegated Birmingham City when his contract expired at the end of June.
And the 31-times capped Sweden international says re-uniting with Bruce, his first manager at St Andrews, was an appealing prospect.
"The gaffer [Bruce] showed an interest in me quite early, a lot of interest, which is obviously nice," Larsson said in the Daily Mail. "He pushed it the hardest to try and get me.
"And I have worked with him before. He took me from Arsenal in the first place and that was an important factor. Knowing him from our time at Birmingham, we worked well. To know what you are going to get from a manager is good.
"He told me all about what he wanted for the club and what the club is all about and when he spoke of his vision for it, it matched my ambitions.
"Also it is a big club, a massive club. I wanted to take the next step and I really feel I have done that by coming here. It has a huge fan base, great stadium and facilities and that is what you want when you play football.
"And the club are trying to push forward. There have been quite a few new signings which hopefully will make the squad better. That is what they told me before I signed - that they were really going to try and have a go. How far that goes, we will have to wait and see."
The Swede was also linked with a return to Arsenal, his first club in England for whom he played 12 first-team matches between 2004 and 2007, but Larsson claims the Gunners' interest was not as solid as Sunderland's.
"Of course signing for Arsenal was tempting to but it never really got that far. There was an interest and then I decided to sign for Sunderland so that was the end of it."
Larsson played more than 200 matches during his spell in the Midlands and was a member of the Blues side which won the League Cup at Wembley against Arsenal in February.
