Here comes the man. It may have taken Schoolboy Q, the rapper born Quincy Hanley on an army base in Germany, a long time to reach this point in the game but he has no intention of slipping out of view any time soon. This is what he does now. On the back of a well-received major label debut album, Oxymoron, which came fast on the heels of a brace of fine mix-tapes that formed part of his apprenticeship, Hanley is sitting pretty.

As gritty hip-hop albums go, Oxymoron is quite remarkable. There's a sizeable coterie of producers and rappers around to give him a dig out – including Pharrrell, Kendrick Lamar, Tyler the Creator, The Alchemist, Raekwon and 2 Chainz – but Hanley is the man pushing this one up the hill. The real rumble is provided by his keen eye for detail and description and the resulting distinctive verses. Beneath the gangsta rubric writ large throughout Oxymoron are superb tales about the hard-knocks of the never-ending street hussle.

The album, Hanley says, is the story of his life to this point. “It’s a dark album because that’s the way things were for me, man. Everything’s bright now, but my past was a different story. It’s about me as a person and being honest about who I am and who I was and my story and the stuff I saw when I was coming up.”

Indeed, it’s fair to say that becoming a rap star is Hanley’s second act. Before he went anywhere near a microphone, he had already experienced life on both sides of the tracks.

“Before I was 21, I’d done a whole lot of shit. I’d been an athlete, a gang member, a drug dealer and I worked a job at the railroad. I was a kid living on the fortunate side when my mother was doing well and I hustled because my homies were hustling and then I ended up having to hustle to survive. And then, I started rapping.”

Rapping as salvation is a common hip-hop meme: youngsters swap a life on the streets for a life in the studio. In Hanley’s case, rap was always there in the background. He remembers listening to acts such as Nas and Jay Z on the bus to school.

When he arrived at school, he found himself learning “nothing that mattered. I needed to know how to survive the day-to-day, not about some history thing.” He’d hear more sense when he stuck his headphones on.

But grabbing the microphone himself and spitting some bars? Nah, not for him in those days. “I know, it’s crazy, right? But I never thought about rapping. It wasn’t, you know, my thing. I had my favourites like Nas and 50 Cent – he changed my way of thinking about music because he was so detailed. I knew that lifestyle that he was talking about and I knew he was for real. He’s like one of my biggest inspirations to do rap. I relate to him a lot in his music. That was real, that had substance – it wasn’t soft.

"It was only when I got out of jail and was on house arrest that I grabbed a pen and started writing and rapping. I was sitting around not knowing what to do. Then I saw the Beef DVD and 50 was, like, 'If you're a felon who just got out of jail and you don't know what to do nigga, rap'. That was it for me, swear to God."

He proved to be a quick learner, the rapper who initially went about his business as Q Mac Mizzle. His rapping skills attracted attention from Top Dawg Entertainment, the rapping start-up already featuring Kendrick Lamar, Ab-Soul and Jay Rock. Suddenly, Hanley found himself in good company.

“I was Kendrick’s hypeman at the start,” he remembers of those days learning the ropes. “I saw him go from having a handful of people at a show to hundreds to sold out. That was a motivation for me, watching him go on and on like that. Now, he’s like a pop star and I want to get up to that next level too.”

But when he started out, there were some issues that had to be sorted. Hanley was selling prescription pills on the street and dealing with his own addiction problems at the same time. As he outlines on Prescription/Oxymoron on the album, this was something that went for on for a while.

“I was selling pills, so pills were always around, so one day I took one to go to sleep and that was it. It was over from there. I was addicted for like two years, and I didn’t tell anybody. Nobody knew. I just stopped one day. One day, I woke up, didn’t have any pills, didn’t go get any more. Just stopped like that.”

These days, Hanley prefers to talk about his experiences on the street, rather than add to them. “I’m not really a gangster any more. I’m a gangster rapper. I’m just telling a story now. I’m rapping about what happened in the past so it’s easy. It’s my life and what I saw so I’ve lived that. I don’t need to any more of that. I just want to work now.”

He stresses too that there’s a lot more to come, as the full Schoolboy Q story is far from told. “I kept some back, man. You don’t give it all away first time out. I didn’t want to tell you all everything and then have nothing to show when you come back around for more. The next album will have more.”

Oxymoron is out now. Schoolboy Q plays Dublin's Vicar St on May 27th