The athletic Monfils booked his place in the deciding match at the eight-man pre-Australian Open tuneup as he beat Roland Garros semi-finalist Jurgen Melzer 2-6, 6-2, 7-6 (7/4) Friday.
Earlier, Australia's former world number one Hewitt overcame Russian Nikolay Davydenko 6-3, 7-6 (7/3).
Monfils is coached by Roger Rasheed, former Australian mentor to Hewitt and a man unlikely to hold back any secrets about the Hewitt game.
"It's great to be in the final," said number 12 Monfils, who stands 2-2 with the Australian.
"I've had two long, tough matches here. And I'll certainly be ready for Lleyton, thanks to having Roger as my coach."
Hewitt's victory is a boost ahead of his tough opening round match at the first Grand Slam of the season, where he faces a reprise of his 2002 Wimbledon final clash against fierce Argentine rival David Nalbandian.
In earlier play after rain spoiled Thursday's programme and the early part of Friday, Melzer defeated 2010 Kooyong finalist Jo-Wilfried Tsonga 8-6 in a pro set to open his weather-delayed account at the event.
The abbreviated match produces a winner in a format where the first player to reach eight games with a margin of two games takes the victory.
Hewitt, whose best performance at the Australian Open was reaching the final in 2005, said that with his game ticking over nicely, facing Nalbandian held no special fears.
The feisty Australian leads the series 3-2, including wins at Wimbledon and in the Australian Open. But he lost to Nalbandian in the Davis Cup six years ago.
"There are no easy draws out there," said Hewitt, now ranked 54th in the world.
"I'll be ready for the first round, Nalbandian or not. We've played each other in some big matches.
"I was near flawless in that Wimbledon final (2002). But we've both moved on a lot since then. I'm hitting the ball well and I'll be ready."
The Australian had a workout against Davydenko as he added a second Russian scalp to his Kooyong record following his win over Mikhail Youzhny on Wednesday's opening day.
Hewitt was broken while up a set and serving for the match at 5-3 in the second, with Davydenko saving a match point to keep his hopes alive.
The set moved into a tiebreaker, with Hewitt regaining his momentum to earn the win.
"It's always nice to beat quality players. Nikolay was hitting the ball well (in the Doha final last weekend). I think we match up well.
"My ball-striking was much better today than against Youzhny. Conditions were more swirly then and today it was calmer. It's always nice to win matches," said Hewitt, who will play the Australian Open for a 15th time.