Now, a day's work might mean going undercover to film people who sell underage girls for sex, going to the Congo to talk to child soldiers, or being held at gunpoint in Papua New Guinea.
Kemp has swapped the scripted world of BBC soap opera for hard-hitting documentaries, and Ross Kemp: Extreme World returns for a third series this month.
The programme sees the intrepid actor meet people caught in some of the most pressing global issues.
On this occasion, the 49-year-old heads to Rio de Janeiro to find out about the crack-cocaine epidemic, treks to Mumbai and Calcutta in India to discover more about sex-trafficking and journeys to Northern Ireland to see how life has changed since the Good Friday Agreement.
While you might think it'd be easy to judge people who have trafficked children or murdered innocent people, Kemp insists on remaining unbiased.
"I can't stand judgment being placed on people, because you don't know them," says the father of a four-year-old son.
"A classic example is the Congo. I go to a hospital where there are 1000 women, most of whom have had their limbs removed before they have been gang raped and I say, 'I want to meet the people who are responsible for this'.
"I want to look into their eyes and find out what can make a human being do this to another human being. When I find the people allegedly responsible for doing these atrocities, the first person I meet is a 13-year-old boy.
"He's a boy soldier who was taken from his mum and dad, had a gun thrust into his hand from the age of six and told to kill people with it.
"They are both victims."
Boy soldiers and child trafficking are far removed from Kemp's own past. He grew up in Barking, Essex, and after graduating from the Webber Douglas Academy of Dramatic Art, he took up his role as EastEnders hard man Grant Mitchell, a part he played on and off for 16 years.
But documentary-making is his passion and, with his 2006 Bafta win for best factual series, for Ross Kemp On Gangs, it seems he's a natural.
That said, he admits that it's hard to switch off from the horrors he sees.
"The older I get, the more it seems to cling to me," he explains. "It's like being a ship; the longer you sail, the more barnacles you get and the more memories you have. Then I go into the edit and see it all again."
Some moments make more of an impact than others on Kemp, who is reported to have secretly married corporate lawyer Renee O'Brien in 2012.
"Afghanistan, in particular, was hard," he says, when within 24 hours of arriving to film Ross Kemp In Afghanistan, he had been shot at by the Taliban.
"You have to go in to the office and make decisions and see the moment you were shot at again, which is odd."
Being involved in extreme situations is something Kemp believes has changed his life.
"I used to be a brilliant timekeeper," he says, laughing. "I'm now the worst timekeeper on the planet. I'm approaching 50. Rapidly, my life has more chaos in it than ever, but I'm also a more considerate human being than I've ever been.
"My family would probably say I'm an emotional misfit, but that's all part and parcel of being who you are," he adds.
"Hopefully what I am and what I do is tell the truth."
l Ross Kemp: Extreme World returns to Sky1 at 9pm on Tuesday, January 21