Expensive new signing Raheem Sterling was fairly quiet on his Premier League debut for City and Sergio Aguero started on the bench but it hardly mattered as Toure bagged a first-half brace and Vincent Kompany headed home a third after the break.
However, the star of the show was City playmaker David Silva, who was a constant danger to the home defence as he showed off his delightful passing repertoire and wonderful close control.
West Brom worked hard but struggled for possession and chances until the game was well beyond them, although they will not have to face such accomplished opponents every week.
Visitors City enjoyed the bulk of the possession in the early stages and grabbed the lead in the ninth minute in somewhat fortuitous fashion.
Jesus Navas cut the ball back to Toure, who produced a weak shot which trickled past a wrong-footed Boaz Myhill via Silva and Craig Dawson, the ball eventually rolling into the net almost in slow motion as the Baggies keeper looked on in horror.
Sterling then caused West Brom problems with a low cross from the left which pinballed around in the area before Chris Brunt blocked Wilfried Bony’s shot.
And City then doubled their lead with a fantastic 24th minute goal from Toure, who exchanged passes with Bony and this time found the roof of the net with a beautifully-struck shot from the edge of the box.
The visitors continued to press forward and Bony had an effort deflect just wide of the post before Sterling wasted a great chance to grab a debut goal, not getting enough power behind his shot after being put through on goal, although Myhill did well to stick out a hand and make the save.
Earlier in the day, West Brom made forward Salomon Rondon their new record signing and he watched on from the stand as Rickie Lambert and Saido Berahino struggled to make an impact in attack for the hosts.
But Berahino was a touch unlucky just before the interval when his neat finish after latching onto a through ball was ruled out, replays suggesting it was very close but that he may have just strayed a fraction offside.
Sterling was denied again by Myhill after the interval but West Brom then enjoyed a decent spell, Lambert putting a free-kick just over and Hart coming out to deny Berahino.
But the wind was taken out of their sails just before the hour when Silva produced a wonderful piece of skill to win a left-wing corner which he floated to the near post, Kompany then using a combination of head and shoulder to send the ball looping over Myhill and into the far corner.
With three points surely assured, City took their feet off the gas somewhat, despite the arrival of Aguero from the bench, and Sterling was taken off with 15 minutes remaining.
But Manuel Pellegrini’s man remained resolute at the back and Hart punched a couple of dangerous crosses clear before gratefully catching a header which James Morrison nodded straight at him.
And the game then ended as it began, with City firmly in the ascendancy, and Myhill did well in the closing stages to keep out a low Aguero shot and an Aleksandar Kolarov free-kick.