He has held the positions since GAZ acquired the Birmingham based light commercial vehicle specialist in July 2006.
Mr Young has left the company to "pursue other opportunities in the industry".
His replacement as a director will be Eugeny Vereschagin, the chief financial officer of GAZ Power Train Division.
An announcement related to the appointment of a new chief executive will follow.
Martin Leach, executive chairman of LDV, will act as interim chief executive.
He said: "The business has gone through enormous change over the last 18 months, with new products, new markets and significant improvements across the board in all aspects of performance.
"Steve provided invaluable leadership in these changes, whilst building confidence in LDV and the MAXUS product as a real alternative to the major players in the light commercial vehicle market."
Mr Young said: "This was not an easy choice for me, but LDV is a great company with a loyal and dedicated workforce, and a highly competitive award-winning product.
"I am confident that LDV will continue to develop and satisfy an increasing number of informed customers around the world. I wish both GAZ and LDV well for the future."