JOHANNESBURG, February 6, 2014 (AFP) - Also on seven under after 65, but on the par-72 East Course, was another Scot, Craig Lee.
The field is split between the East and West Courses for the opening two rounds before the action descends on the East lay-out for the weekend.
Forsyth, a two-time European Tour winner who has had to go back to Qualifying School, needed just 30 shots to reach the turn.
"The front nine was probably as good as I've played in a long time," he said.
"I seemed to do everything right on the front nine, but I struggled a little on the back, where I ended up between clubs a few times. No dropped shots and seven birdies, so I'm never going to complain with that."
The 32-year-old Molinari has been impeded by a string of fitness issues since making his Ryder Cup debut alongside brother Francesco at The Celtic Manor Resort in 2010.
Having finished tied for ninth in Dubai last week, the former US Amateur Champion was once again in fine form.
Three British Open Championship places are on offer to the best-placed players in the top 10 not already exempt, with all of the leading trio yet to secure an invite to Royal Liverpool.
Lee admitted that the added incentive of a major Championship debut was spurring him on.
"It's really hard to figure out where you are in the field with two golf courses, and with the east being slightly tougher I feel like I'm in a good position," he said.
"If we can keep the same level of golf then we might be able to separate ourselves from the bunch.
"You don't really change your strategy, but it's a great reward for three lucky guys who'll get a chance to play in The Open."
Walters is also seeking a maiden major appearance - but may elect not to go to Hoylake even if he qualifies because his girlfriend is due to give birth that week.
Leading scores on Thursday in the first round of the $1.77m Joburg Open on the European Tour on the East and West Courses of the Royal Johannesburg and Kensington Golf Club (pars 71 and 72):
64 - Alastair Forsyth (SCO), Justin Walters (RSA), Edoardo Molinari (ITA)
65 - Craig Lee (SCO), Graham Van der Merwe (RSA), Edouard Dubois (FRA), Hennie Otto (RSA), George Coetzee (RSA), Robert-Jan Derksen (NED), Danie Van Tonder (RSA), Jin Jeong (KOR)
66 - James Heath (ENG), Gary Stal (FRA), Drikus Van der Walt (RSA), Andy Sullivan (ENG), Shaun Norris (RSA), Damien McGrane (IRL), Justin Harding (RSA), Jean Hugo (RSA), Torben Baumann (GER)
67 - Richard Sterne (RSA), Ricardo Santos (POR), Jorge Campillo (ESP), Tyrrell Hatton (ENG), Mikko Korhonen (FIN), Keenan Davidse (RSA), Mark Murless (RSA), Steven Ferreira (RSA), Richard Bland (ENG), Steve Slurry (ENG), Jason Knutzon (USA), Scott Jamieson (SCO), Lee Slattery (ENG)