The incident happened between 9.15pm and 9.40pm on Friday, September 20, on the Banknock side of the Braeface Road, also known as Kelt Road.
The man was found by passers-by and was taken by the Scottish Ambulance Service to hospital where he remains in a serious but stable condition.
Detective Sergeant Will Hogg, of Falkirk CID, said: “We have already spoken to some people who were in the area at the time but would like to speak to anyone who has not yet come forward.
“The man was wearing a cream coloured jacket, carrying shopping bags and travelling from the direction of Banknock.
“We are particularly keen to speak to anyone driving in the area around the time who may have dash-cam footage that could help with our enquiries.
“We would urge anyone with information to contact Falkirk CID on 101, quoting incident 4802 of 20 September.
“Alternatively, they can make an anonymous call via Crimestoppers on 0800 555 111.”