The AIS 24-year-old took things easy in the qualifying round, finishing in sixth place, but then stepped it up in the final to make his fourth podium in a row.
Following the event, Begg-Smith donated his second place prize money to the Haitian relief effort.
"I'm glad to be able to make this donation to the Haitian relief effort," Begg-Smith said.
"The devastation and trauma that these people have endured is horrific."
"Hopefully we can collectively band together as a society to help in the recovery efforts."
French skier Guilbaut Colas collected the Deer Valley victory, his first for the season, with 26.80 points, 0.59 points ahead of the Australian.
Defending World Cup champion Alexandre Bilodeau of Canada rounded out the minor medals on 25.95 points.
"Dale was quite conservative in qualifying," said Olympic Winter Institute CEO Geoff Lipshut.
"Then he put down a very good run in the final after swapping lanes just before it."
"He was very fast, very clean, and it was a great effort to get second. It just shows his great adaptability."
The result stretched Begg-Smith's lead on the World Cup standings, his 475 points putting him 123 clear of nearest rival, Jesper Bjoernlund of Sweden.
Colas, who looms as a serious medal threat in Vancouver after claiming silver in the opening Deer Valley event, is in third place, despite missing the season's opening two World Cups.
NSWIS athlete Matt Graham was in 27th position, an impressive pb performance in just his second World Cup appearance, while Begg-Smith's AIS team-mate Sam Hall finished in 35th place.
NSWIS skiers David Graham and Hugh Norton were in 38th and 53rd places respectively.
In the women's event, 15-year-old NSWIS skier Britteny Cox was also impressive, finishing in 29th place in her second World Cup event.
Team-mate Sarah Melville was two places further back, while Nicole Parks (33rd), Roanna Humphries (34th) and Taylah O'Neill (42nd) were also in action.