The 32-year-old, belted 15 fours and brought up his century off just 118 balls.
Lehmann backed up his aggressive first-innings 103 with a well-crafted 93 as SA went to stumps on day three at 5-298, leading Victoria by 275 runs at the MCG.
Lehmann combined with Callum Ferguson (140 not out) for a 212-run partnership to put the Redbacks in the box seat to claim their first victory for the season.
Test wicketkeeping candidate Alex Carey was unbeaten on eight after Tom Cooper (12) was run out shortly before stumps.
The left-hander was dropped on 64 by Glenn Maxwell at gully off the bowling of Chris Tremain and went on to make Victoria pay.
Lehmann hit nine fours and looked in excellent touch before attempting an ill-timed sweep shot to legspinner Fawad Ahmed and was caught by Aaron Finch at short fine leg.
With Lehmann taking his time at the other end, Ferguson was the aggressor, scoring the highest total of the Shield season so far.
Head, who scored 67 in the first innings, survived a dropped catch before Ahmed (2-97) had him caught behind on four.
Tremain (1-39) and Scott Boland (1-37) combined to account for Redbacks openers Jonathan Dalton (10) and Jake Weatherald (21).
Worrall (3-61) and Chadd Sayers (3-60) were the pick of the Redbacks' bowlers.
In the Toyota Futures League game, also in Melbourne, Victoria reached 7/340 on day one.
Elliot Opie was the most successful Redbacks bowler, taking 3/49 from 19 overs, and Tom Andrews picked up two wickets.