The Sunbeam Alpine, introduced by Rootes in 1959, lacked the power to compete in world markets. Rootes initially approached Ferrari to develop a more powerful engine, but negotiations failed. In 1962 racing driver Jack Brabham proposed to Rootes competition manager Norman Garrad the idea of fitting a Ford V8. Ian Garrad, Norman's son and the West Coast Sales Manager for Rootes in America, lived near Carroll Shelby's operation, which had recently done a comparable V8 conversion on the AC Cobra.
Ian Garrad commissioned racing driver and fabricator Ken Miles to build a quick proof-of-concept prototype. Given a budget of $800, a Series II Alpine, a Ford V8, and a two-speed automatic transmission, Miles had a running car within about a week, confirming the conversion was feasible. Shelby then began work on a more polished prototype — the "white car" — in April 1963, using a Ford 260 V8 and a four-speed manual transmission. The Ford V8 was only 3.5 inches longer than the Alpine's four-cylinder engine, though fitting it required every available inch of the engine bay.
Lord Rootes, initially unaware of the project, insisted on driving the Shelby prototype himself after it was shipped to England in July 1963, and was sufficiently impressed to contact Henry Ford II directly to negotiate an engine supply deal. Rootes placed an initial order for 3,000 engines — the largest single order Ford had received from an automobile manufacturer — and decided to launch the car at the April 1964 New York Motor Show, just eight months away.
Rootes contracted body assembly to Jensen at West Bromwich rather than giving it to Shelby, whose closeness to Ford made Rootes uneasy. Jensen was available after its Volvo P1800 assembly contract had been cancelled. Painted and trimmed bodies came from Pressed Steel in Oxfordshire; engines and gearboxes arrived directly from Ford in America. The car was renamed from its working title Thunderbolt to Tiger, the name inspired by Sunbeam's 1925 land speed record car.
The Tiger went into production in June 1964. Jensen could assemble up to 300 Tigers per month. The standard Ford 260 V8 produced 164 bhp at 4,400 rpm, giving a 0–60 mph time of 8.6 seconds and a top speed of 120 mph. Kerb weight rose from the Alpine's 2,220 lb to 2,653 lb, with the extra front weight balanced by a Panhard rod and stiffer front springs.
Two official variants were produced across a total of 7,128 cars. The Mark I (1964–1967) used the 260 cu in Ford V8; enthusiasts refer to later Mark I cars built on the Series V Alpine bodyshell as Mark IA. The Mark II, of which only 633 were built in the final production year, received the larger 289 cu in Ford V8, which reduced the 0–60 time to 7.5 seconds and raised top speed to 122 mph. The Mark II was intended exclusively for export to the US and was never marketed in the UK, though six right-hand drive examples were sold to the Metropolitan Police for traffic patrol and high-speed pursuit work.
Three racing Tigers were built for the 1964 24 Hours of Le Mans, fitted with fastback coupe bodies by Lister. Both entered cars suffered early mechanical failures caused by engines that had not been properly developed; Shelby eventually refunded the development cost to Rootes. All three Le Mans Tigers survived.
Rootes achieved greater success in European rallying. The Tiger took first, second and third at the 1964 Geneva Rally. In the 1965 Monte Carlo Rally, one Tiger finished fourth overall — the highest placing by a front-engined rear-wheel drive car — and another eleventh. At the 1965 Alpine Rally a Tiger crossed the line as outright winner but was subsequently disqualified for running undersized cylinder head valves. On the drag strip, the Tiger held the American Hot Rod Association's national record in its class for two years, running a quarter mile in 12.95 seconds at 108 mph.
When Chrysler acquired a controlling interest in Rootes in 1967, it faced the problem that its own V8 engines were either too large to fit under the Tiger's bonnet or had the distributor in the wrong position. Chrysler ordered production to cease once Rootes' stock of Ford V8 engines was exhausted. Jensen assembled the last Tiger on 27 June 1967.
The 1965 Tiger Mark I appeared in the American television spy comedy Get Smart, driven by Maxwell Smart in the opening credits of the first two seasons. Don Adams, who played Smart, later gave the car to his daughters. The Tiger also appeared in the 2008 film adaptation; a replica had to be constructed using a standard Alpine as no available Tiger could be found in Canada, where the film was produced.
The Tiger demonstrated that a carefully engineered V8 transplant could transform a modest British roadster into a genuine performance car. Its short production life — killed by a corporate takeover rather than any failure of the car itself — and the ease with which examples can be modified have left few surviving Tigers in standard form, making original unmodified examples among the more collectable British sports cars of the 1960s.