This was an unexpected development that took the British car industry watchers by surprise.
Tata Motors managing director Ravi Kant will temporarily take over Smith's duties and assume day-to-day responsibility of the firm until a replacement is found.
No official explanation was forthcoming for Smith's abrupt exit which came after talks over worker's pay and conditions broke down between unions and company officials.
A JLR spokesman said Smith's departure is not linked to the talks and that the company would like to thank him for his efforts in the role and for his service to Jaguar and Land Rover over many years. Smith has been with the firm for over two and a half decades.
JLR was acquired from Ford by India's Tata Motors in June 2008 for $2.3bn.