The prince of grime comes of age

The pint-sized rap star Tinchy Stryder, who opened the Pyramid stage at Glastonbury this summer, looks far younger than his 23 years as he sits engulfed in a swivel chair, drinking apple juice.

He is wearing a Star in the Hood T-shirt from his own clothing range and has just gone into business with his childhood hero, Jay-Z, to sign new acts to their record label. Their new entertainment company, Takeover Roc Nation, which they formed last month, is based in the UK, and will handle management, merchandise, records and ticket sales for its artists.

He is also releasing his new single "In My System" next month. It is taken from his forthcoming album Third Strike, out in November.

We meet in Brixton where the rapper is being filmed for the Disney XD channel in his new role as music mentor. One teenage boy will win the chance to shadow him for a day in a recording studio, for a "dream mentorship".

He tells me that he didn't have a mentor himself at the start of his career, but Jay-Z is proving to be quite helpful these days. "I finally met Jay-Z in his dressing room after his show in Manchester in June. He was with his wife Beyoncé. His people wanted us to link up for ages before then but we kept missing each other. Later we had a drink. He said: 'People always say they can handle it at the start. You have to pace yourself.' He wasn't referring to the drink but to success. He says key things; he is not someone who speaks for the sake of it."

Stryder has had two No 1 hits since 2009 – "Number 1", a collaboration with N-Dubz, and "Never Leave You", featuring Amelle Berrabah from the girl band Sugababes. He has led the way for the next generation of golden boys of British urban music, including Tinie Tempah and Chipmunk – now Bashy is now rising through the ranks too.

Fame has a price, and Stryder has used these issues as material in his deeper and darker-sounding new album. This was on the advice of his old friend Dizzee Rascal, who grew up with him on the same East London music scene, where they MC-ed together at youth clubs in Bow.

"My new album is about what's been on my mind and all the things I went through since I've been successful this last year," says Stryder. "It's a bit deeper. A lot of people from the outside looking in, think it's all rosy and good. I can't complain – it has been fun. But there are a lot of deeper issues with my social life, friends and family, where I feel separate because I am so busy. Often I feel lonely in a crowd. I don't actually blame anyone for not understanding. One song, "Walk This Road", is about how you will never understand unless you are in my shoes. I was speaking to Dizzee about it and he said the trick is to translate these feelings into my music. When you write it down or record the music you feel much better. It's off your chest. This time there has been a bit more time and planning for the album and I've thought about a lot more things. Most tracks on there are about something personal."

His new single, "In My System", covers his usual subject matter of young love and girls. "I say, 'How did you grab my soul like that?... How did you get through the doors on latch?...' It's quite deep. You don't really understand how those things happen. But in the blink of an eye, you wonder how a girl has got such a hold on you."

The Ghanaian-born rapper, whose real name is Kwasi Danquah, was renamed Tinchy because of his short build. He comes from a large and religious Catholic family who moved to London when he was a young boy, and lived in a Tower Hamlets council estate. He attended St Bonaventure's Catholic comprehensive school in Forest Gate, Newham, began MC-ing in the playground at the age of 12 and soon became a member of the Ruff Sqwad crew.

He didn't always want to be a pop star – he played football for Wimbledon youth team. "I wanted to be a footballer– that was my thing. Music was just a hobby but it just naturally happened the way it happened. I got to a stage where music overtook football."

While he was still at the University of East London, studying for a degree in digital arts and the moving image, he rose to mainstream stardom with his single "Take Me Back", a collaboration with Taio Cruz, which went to No 3 in January 2009. " I always felt like I wanted learn more. When you are doing music videos, it is interesting to know how it all works."

Everything changed for Stryder when he appeared at a grime night in Norwich. The club's promoters, Archie Lamb (the son of Norman Lamb, the Liberal Democrat MP for North Norfolk) and Jack Foster asked to manage him and funded his 2007 album Star in the Hood via Star in the Hood T-shirts sold at gigs and on eBay. Not only did the trio tour the country in Lamb's dad's car but Norman Lamb also re-mortgaged his house to help his son put out Stryder's first records. Archie's father's investment paid off when the single "Stryderman" made the Radio 1 playlist in early 2008 and catapulted him into the singles charts. Island Records then signed him. The song was taken from his second album, Catch 22, which debuted in the charts at No 2.

It was the start of a partnership with producer/songwriter Fraser T Smith, who produced his new album, and had experience crossing urban over into the pop mainstream, having worked with Kano and Craig David.

"It's been more than 10 years to get to this point. I never felt like it has ever taken long because I was never in a rush to get anywhere," says Stryder. "I just did it because it was fun and I enjoyed it. It was a hobby to start with."

Stryder doesn't mention any business ventures unless asked. In fact he looks quite downcast. Even his Star in the Hood T-shirt logo is hardly noticeable under his jacket. He seems more interested in his music, but doesn't want to wonder in advance whether "In My System" will give him his third No 1. "Gangsta", the first song off the new album, which was only released as a video, reached No 67 in the UK singles charts. "You are only as good as your last song," he tells me.

But if Stryder, who has been MC-ing and passionately making music since he was 12 years old, could look upon anybody as a mentor, it is the rapper Wiley, also from Bow, who christened him Prince of Grime. "Just being around Wiley I learnt a lot off him, especially about being confident on stage, which can be scary at first," says Stryder. "I write lyrics and some people might not have the confidence to do that. From what I've learnt sometimes you have to look into yourself. The best music is from the heart."

"In My System" is out on 9 August. Tinchy Stryder is at Underage Festival on 1 August. Disney XD's Aim High Mentorship Programme is at Disneyxd.co.uk/aimhigh