Past
Shigeru probably didn't have a hard life, in fact, maybe he could've been spoiled. If he wanted something, he got it instantly. Maybe. It could explain his present-day-attitude. Shigeru was here, Satoshi is a loser! Also, you notice that he travels in style, but right now I'm starting to get into present.

But Shigeru must've spent a lot of time studying Pokemon, because it seems he's pretty good at training them. But then , he's the grandson of the greatest Pokemon Professor.

Present
He's doing pretty well in his Pokemon training career. He has over 200 pokemon, all of them supposedly pretty strong. He has a shiny red car with 6 (pretty) cheerleaders. And he has 10 badges. His two main pokemon seem to be Arcanine and Nidoking. Both are pretty strong. I suspect they're his strongest pokemon, but only the person who created Pokemon know. Then again, even he might not know. Ah well.

Shigeru is a little (or big) of a snob. He has this weird voice (I suspect it came from the 4kids studio, but I'm not going to say anything) that I wish would be replaced. He is very confident, I think it's to keep his cheerleaders supportive (I swear, they're hired!)

He appears to love winning. It's also pretty evident he also likes travelling in style.

Future
Here are some opportunities he may have when he's older.

He'll become a Master
Why not? He's got what it takes. He's also Satoshi's main rival, don't forget that.

He'll become a Pokemon Professor
If he can't become a master, maybe he'll become a professor. His grandpa is, I think he'll be pretty supportive of that.

He'll become a gym leader
He is a gym leader in Gold/Silver. He's the gym leader of the Viridian City gym