The three-time Indy500 champion sustained a concussion and fractured his spine and right ankle after colliding with Takuma Sato's car and slamming in to a fence at the Houston Grand Prix in Texas on 6 October (13).
He was discharged from a hospital in Indiana after undergoing his second surgery on 14 October (13), and was hoping to make a racing comeback in the spring (14).
However, the 40 year old has since been advised it is in his best interests to hang up his helmet and racing gloves for good.
In a statement, released on Thursday (14Nov13), the Scot says, "I am eternally grateful for the medical care I have received over the last several weeks. I'd also like to thank my family and friends for their unbelievable support.
"One month removed from the crash and based upon the expert advice of the doctors who have treated and assessed my head and spinal injuries post accident, it is their best medical opinion that I must stop racing. They have made it very clear that the risks involved in further racing are too great and could be detrimental to my long term well-being. Based on this medical advice, I have no choice but to stop."
Franchitti began his driving career in the early 1990s in his native U.K. and raced in the IndyCar Series from 2002 to 2007. He quit briefly for a stint in Nascar, but returned to IndyCar in 2009, winning three consecutive Series titles. He also celebrated winning three Indy500 races in 2007, 2010 and 2012.
He separated from actress Judd in January (13), but the couple has remained close and she raced to his side following his career-ending crash in Houston.