James Robert Stewart was born at the hamlet of Milton, outside Dumbarton, Scotland. Although expected to work in his father Bob's well-known Jaguar dealership and garage at Dumbuck, next door to his home, Jimmy had other ideas.
He was allowed to drive the new Jaguars delivered to his father's garage along the winding, narrow roads alongside Loch Lomond, down to Arrochar, and up to Oban. The new Jags were so well "run in" before they were delivered to their owners that they usually needed an oil change.
After cutting his teeth on hill-climbs and scratch races in 1951-52 with a Healey Silverstone, Jimmy became an integral part of the Ecurie Ecosse team the following year, racing both the Jaguar C-Type and XK120 with great success. His father, Bob Stewart, had quietly paid for the C-Type Jaguar (XKC 041) registration number KSF 181, and it was added to the Ecurie Ecosse stable.
In the early 1950s Jimmy Stewart was drafted for compulsory national service in the Royal Electrical and Mechanical Engineers (REME). Fortunately his commanding officer was a keen motor racing enthusiast and Stewart ended up racing at weekends while his fellow soldiers were peeling spuds.
He was then given the chance to race the Ecurie Ecosse F2 Connaught and Cooper-Bristol which were bought for the team by Major Edward Thomson of the Ben Line shipping company.
In the British GP of 1953 he ran in sixth place and was going very quickly indeed, before spinning into retirement after 79 of the 90 laps.
Back with the Ecosse C-Type in 1954, Stewart continued to build a reputation as a very fast and fearless driver. He won three races in one meeting at Goodwood, but his season was soon cut short by injury when he was involved in a collision at Le Mans and thrown from his aerodynamically suspect works DB3S coupé, suffering a fractured elbow.
He was back in 1955 with Ecurie Ecosse but during the Eifelrennen at the Nurburgring he crashed the D Type and was trapped under the car for 10 minutes before help arrived. This time he decided to retire.
Later, though he'd been retired for several years, Jimmy played a part in getting his younger brother onto the first rung of his professional career. When Ken Tyrrell was looking for a new driver for his F3 team, and had Jackie Stewart recommended to him, he phoned Jimmy to ask if his brother was serious about racing!
He then worked in vehicle sales in the UK and America, and beat a 40-year battle with alcoholism in the late 1990s before setting up home close to where he grew up near Dumbarton in Scotland.
In his recent Autobiography, Jackie Stewart said: "I owe him almost everything because, when I was young and struggling at school, the world seemed a dark place, I found my real salvation in motor racing. But I only found it because, in my difficult time of need and confusion, it was my older brother who carried the torch and selflessly showed me the way. It was almost as if Jim was beckoning me to join him on a magic carpet ride, carrying me out of the wilderness at school into the exciting, glamorous world of motor racing."
The two brothers had never been so close and Sir Jackie, who had cut short a Christmas holiday cruise, was with him when he died.