Yesterday evening, viewers discovered that Zak was responsible for last month's brutal attack on his son Cain (Jeff Hordley), which saw the bad boy beaten up and left for dead.
Zak took matters into his own hands after Cain set out to destroy a number of lives in the village, but Halliwell today told This Morning that he did not agree with his alter ego's terrible decision.
Halliwell explained: "I would say that violence… it's not something that you should use, really. I don't think it should ever be used. I think we should sort our problems out without it."
Pictured: Steve Halliwell on This Morning.
Speaking of how he prepared for last night's emotional showdown scenes between Zak and Cain, he continued: "I was upset, generally, thinking about a situation where you'd lost your mind so much that you've nearly killed your own son.
"I just thought of relatives, my daughter, and tried to translate it to that. It's unbearable to think you might be able to do that."
The actor also admitted that some suspicious viewers had been shouting at him in the street over Cain's attack in recent weeks.
He said: "I think some people did start to [suspect]! Usually people shout, 'Where's your cap?' in the street. But I started getting, 'You did it!' So I think some people had rumbled it!"
Emmerdale continues tonight at 7pm on ITV1.
> Emmerdale Zak revealed as Cain's attacker
> Emmerdale Steve Halliwell on Zak Dingle's dark crime and future
> Read more Emmerdale spoilers and news