Wilfried Bony also struck twice as the Barclays Premier League leaders made light of the absences of key attacking duo Sergio Aguero and David Silva at the Etihad Stadium.
But with star striker Aguero likely to be out for at least a month and playmaker Silva for a fortnight, Sterling is aware there are tougher challenges ahead.
They start with Sevilla in the Champions League on Wednesday before City then travel to Old Trafford for next Sunday's derby against Manchester United.
Sterling said: "It is always good to be on the scoresheet and even better to get a hat-trick
That was my best game so far for City - I had chances and I finished them so I'm happy.
"But the game has gone now and I need to focus on the next game and hopefully try to get on the scoresheet then
We have to put this game to one side now and look towards Sevilla and Man United next weekend."
Sterling played just behind lone striker Bony with the outstanding Kevin de Bruyne to his left and Jesus Navas on the right.
Bournemouth did have a good early penalty appeal rejected but City's attack soon started to fire as Sterling and Bony both struck in the opening 11 minutes.
Glenn Murray replied but Sterling showed great composure to net another after being released by a brilliant De Bruyne pass and completed his treble before the interval, although Navas should have taken the initial chance.
Bony claimed his second with a neat turn in the closing minutes and Kelechi Iheanacho had another effort ruled out for offside.
The performances of the forwards, and particularly of De Bruyne and the understanding between Bony and Sterling, were among the highlights and bode well for City at a time when squad depth is being tested.
Sterling said: "The movement up front and the passing from midfield has been really good in the last few games and we've been playing some good, free-flowing stuff.
"I thought Wilf was unbelievable
He brought people into the game and scored goals when he needed to
That was a credit to him."
For Bony there was also great satisfaction
His City career is yet to get going with a combination of international commitments, injuries and illness - now revealed to be malaria - having hampered him since his £25million January move from Swansea.
Bony said: "This is a good chance for me and it started to work, so let's hope it carries on like this."
Bournemouth's preparations had been disrupted when goalkeeper Artur Boruc aggravated a thigh injury in the warm-up and had to be replaced by Adam Federici.
It was the latest in a series of injury problems to hit the promoted side, having already lost Tommy Elphick, Callum Wilson, Max Gradel and Tyrone Mings to long-term problems.
Manager Eddie Howe said: "With our full squad this would be an incredibly tough task and it is even more so with the players we have out.
"But we are going to have to cope
I still believe the squad we have got is able to be competitive, despite the fact we have so many players out long term
We are not looking at that as an excuse."
Source : PA
Source: PA