The Cats led by just seven points early in the final quarter of Sunday night's match, and Eagles forward Noah Long had the chance to close the margin to one point with his 35m set shot.
But Long's miss proved costly, with Geelong kicking seven of the next eight goals to secure the 17.14 (116) to 11.7 (73) win.
Cameron was restricted to one goal across the first three quarters under the tight attention of Reuben Ginbey, but the star forward exploded late to blow out the margin.
Smith tallied five clearances, one goal and 834m gained to go with his 38 disposals.
He already had 25 disposals to his name by halftime before a tight tag from Brady Hough slowed him somewhat.
Max Holmes (27 disposals, seven clearances) was also influential for Geelong, who improved their season record to 8-4.
"He just kept getting the ball early," Geelong coach Chris Scott said of Smith.
"I thought he and Holmes were really penetrating."
West Coast coach Andrew McQualter saw plenty of positives despite the late blowout.
"I thought we competed, and maybe even spooked them a little bit for that period of the game," McQualter said.
"I thought we had them ... not on the ropes, but we had them a little bit under pressure there for two quarters, which is a good sign.
"But their class was able to shine through in the end."
West Coast co-captain Oscar Allen kicked four goals in his best match of the year, while Liam Baker was prolific with 29 disposals.
Smith ran riot in the opening quarter, tallying 15 disposals and four clearances to help give Geelong the early ascendancy.
The Cats were wasteful at times but kicked 4.5 to 2.0 for the term, with Gryan Miers' second goal coming on the quarter-time siren.
Smith racked three disposals and a goal within a minute of the second quarter starting as Geelong threatened to run away with the contest.
The lead extended to 29 points a few minutes later when Brad Close picked off Matt Flynn's horror across-the-goal pass to snap truly.
Allen helped drag West Coast back into the match.
The co-captain kicked two goals and laid off another to Noah Long with a brilliant handball to help spark life into the home side.
It proved infectious, with West Coast players dramatically lifting their pressure to put the heat on Geelong for the first time in the match.
The 42,501 crowd went wild when Harley Reid pounced on a Geelong blooper to kick his first goal of the match, reducing the margin to 11 points by half-time.
Two goals apiece in a third-quarter arm wrestle meant the margin was still 11 points entering the final term.
Elijah Hewett's high snap got the ball rolling for West Coast in the final quarter, but Long's miss a short time later proved crucial.
Ollie Dempsey, Tyson Stengle and Rhys Stanley hit goals in quick succession, before Cameron ran riot with four majors for the term.
