The incident occurred just as Celtic’s Gary Hooper had put Hoops two goals up on the homeside.
Before the game could restart a bigot jumped from the Hearts section of the main stand and ran towards Lennon, landing a punch before he was wrestled to the ground.
There were cheers from a section of the Hearts fans.
The thug was handcuffed and dragged away by stewards and cops.
Scottish Football Association chief executive Stewart Regan issued a statement, saying: “Clearly this kind of behaviour from supporters is wholly unacceptable.
“The safety of players, club officials and match officials is paramount on or around the field of play, and this clear breach of security is a matter I will be discussing with SPL chief executive Neil Doncaster tomorrow.”
Co Armagh man Lennon has been in the headlines regularly this season.
In January a package addressed to him containing bullets was intercepted at a sorting office in Country Antrim.
In March, the club confirmed Lennon was under 24-hour security surveillance after a suspicious package was intercepted at a Royal Mail sorting office in Saltcoats, Ayrshire.
On 19 April it emerged that Royal Mail intercepted a total of two “viable” parcel bombs addressed to Lennon.