With the Renegades needing 22 runs from the final over for victory on Friday night, paceman Ben Dwarshuis (3-36) stepped up for the Sixers only days after the sudden death of his father.
"It was up to him to play tonight, he was keen to get out and play. That shows real courage," Smith said.
Dwarshuis bowled Tom Rogers with the first ball of the over before conceding a six from all-rounder Will Sutherland, the side's last hope, who kept the game in the balance on the second night of the BBL season.
But Sutherland (50) swung and missed at Dwarshuis' penultimate delivery of the game, which was then out of the Renegades' grasp with one ball remaining.
The Renegades finished on 7-167 in reply to the Sixers' 6-175 and have not beaten them in four years.
Young gun Jake Fraser-McGurk (48) was the only man who seriously threatened for the Renegades in the top order, just missing out on his first BBL half-century.
"There's just some things to polish up on. It's a pretty strong squad. I feel like if we can get it right, get that polish, we'll go deep," said Renegades spinner Adam Zampa.
Picked in the team of the tournament after a five-game cameo last summer, Smith was pleased to have had a chance to don the magenta again before the Perth Test begins next week.
"It's good to have your Australian players play whenever they can. It helps grow the tournament, I've always tried to come back every chance I've had," Smith said.
Smith picked up where he left off last BBL summer, setting the tone for the Sixers with his top score of 61 out of their 6-175 after they lost the toss.
After the Sixers lost 2-2 from Sutherland's bowling, Smith steadied the ship during a 69-partnership for the third wicket with a favourite co-conspirator in Moises Henriques.
Smith brought his seventh BBL half-century with a single off Sutherland, who finished with 2-21.
It took long-time Australian teammate Zampa (2-24) to dismiss Smith in the 17th over and prevent the all-out carnage that had crowds flocking to see him last summer.
Also playing his first match on home soil since their one-day World Cup triumph, Zampa enticed Smith into skying a shot to deep square leg, where he was caught by Jono Wells.
Zampa threatened to turn the game on its head as he bowled English all-rounder Tom Curran for a golden duck with his next delivery, but he missed out on his maiden BBL hat-trick.
A rare clash for Smith with Test teammate Nathan Lyon was put on ice as the superstar off-spinner missed the game to ready himself for next week's Perth Test.
Smith is hoping to play for the Sixers once more this summer in a clash with the Sydney Thunder on January 12, that falls between the Pakistan and West Indies Test series.
11°C