Not unlike tenured professors, in the 93 years that General Motors Corp. has been creating cars and trucks, only five executives have headed the design department.

Of course, in the early days, GM and the rest of the industry put their full support behind their engineers. The craftsmen who engineered and manufactured the vehicles were the only voices of authority on how their products looked.

But that all changed in 1927 when GM hired an immodest, flamboyant Californian. He was Harley Earl, described by a former employee as first and foremost a genius, but also an egotist and a tyrant. Mr. Earl rightfully can claim to be the father of automotive design for all of the industry.

Another genius, but with extraordinary organizational skills, Alfred P. Sloan Jr., asked Mr. Earl in 1927 to head the design staff after the Californian directed the styling of the 1927 LaSalle under a special contract with Cadillac. Mr. Sloan named the new department Art & Colour. It was renamed Styling in 1937. After Mr. Earl became the first styling vice president in the industry in 1940, the department stayed under that name until 1956 when it was given its current title of Design Staff.

Harley Earl, a close friend of noted movie director Cecil B. DeMille, even wore the jodhpurs associated with movie directors in the silent film area. Before his GM appointment, Mr. Earl had fashioned car bodies for many stars including Douglas Fairbanks, Mary Pickford, Roscoe (Fatty) Arbuckle and Mabel Normand.

“Harley Earl and his successor, William Mitchell, ran the design staff, and what they said usually went,” recalls George Moon, who retired in 1987 as executive director of interior design after a GM career of 35 years. “Omnipotence was a characteristic of both Earl and Mitchell, but they did occasionally defer to powerful division heads like Ed Cole, Bunkie Knudsen or Pete Estes.”

Mr. Moon adds: “John DeLorean always seemed to be on the young side, and he was aggressive on what cars needed to be salable. DeLorean had great ideas like the Pontiac GTO in the '60s, but he was too much for a very conservative corporation.”

Another innovation from Mr. Earl was the use of clay models, instead of wood. Among the Earl-inspired innovations that made design a key sales attraction and inspired the annual model change were the elimination of the running board, the separate strapped-on luggage compartment and the exterior spare tire. Luggage and the spare moved inside the longer, lower cars. The running board departed as vehicle heights shrunk and allowed passengers to enter without the step support. Other innovations from Mr. Earl include the hardtop body style, non-glare windshields and the fiberglass body, notably on the Corvette sports car.

Mr. Moon says he thinks Harley Earl's best design was the 1957 Chevrolet that reached classic status after it became a used car. Chevy completely changed the design in the 1958 model year.

Through the years various GM chiefs also made their marks on vehicle design. Chairman Frederic G. Donner (1958 to 1967) always checked the interiors with a single focus — the clock on the instrument panel. He insisted that the numbers on the clock were clearly visible, but didn't seem to worry about the timer's accuracy, which did not occur until the chronometer was installed in the '70s. John F. Gordon, president under Mr. Donner, queried about the size of the ashtray

A GM entry that is regarded as one of the all-time top designs is the 1959 Cadillac, with its 18-in. high rear fins. Both Mssrs. Earl and Mitchell shared in that conception.

Mr. Moon recalls a time when Mr. Earl blew up, but later relented. He was on a farewell tour of Europe before stepping down in 1958. Prior to his overseas departure in 1957, he left Mr. Mitchell, Chuck Jordan and others, including Mr. Moon, to run the show. “Those 1959 designs would have been the ugliest vehicles ever designed,” Mr. Moon asserted. “Several of us drove down to Mound Road and saw a crop of super low, high-finned 1957 Chrysler, Dodge and DeSoto products. We could not believe what we saw and realized that what we were doing was so bad. We made sketches and returned to shove the Earl designs aside. Harley Earl came back and was shocked by our action and threatened to fire all of us. After he understood what was happening, he changed his mind, and we persevered.”

Mr. Earl's other design that is best forgotten was the 1929 Buick, which critics quickly dubbed the “pregnant Buick.” Mr. Earl sent a note to his mentor and good friend, Alfred P. Sloan, which was published in Mr. Sloan's book, My Years with General Motors. The letter explained:

“I designed the 1929 Buick with a slight roundness both ways from the beltline highlight, and it went into production. Unfortunately, the factory, for operational reasons, pulled the side panels in at the bottom more than the design called for. In addition, five inches were added in vertical height, with the result that the arc I had plotted was pulled out of shape in two directions, the highlight line was unpleasant and the effect was bulgy.”

Mssrs. Earl and Mitchell (1958 to 1977) had the most to do with Mr. Moon's progress at GM. Mr. Mitchell's early favorites were the split-window Corvette and the Buick Riviera. The Riviera originally was planned for Cadillac under the revived name of LaSalle. Cadillac rejected the design and Buick took it on as the Riviera. Cadillac, according to Mr. Moon, was fearful that the LaSalle would encroach on the DeVille market.

The new front-wheel-drive Seville temporarily was named LaSalle, but GM Chairman James M. Roche (1967-1971) feared it wouldn't mean much to affluent buyers in their 40s. Holes were already punched in the fenders for the LaSalle nameplate, but Seville fit the same spots. Mr. Roche was in on the early planning because the Seville did not go on sale until the 1976 model year.

Irvin Rybicki moved into the top design spot in 1977. Not a flamboyant leader like his two predecessors, Mr. Rybicki was a victim of corporate penny-pinching. “Sharing among the car divisions was an order from the 14th executive floor,” says Mr. Moon. Under the regime of Mr. Rybicki, the so-called 1982 model cookie-cutter J cars — Cadillac Cimarron/Chevrolet Cavalier/Oldsmobile Firenza/Pontiac J 2000/Buick Skyhawk — were particularly indistinguishable. Business Week magazine at the time ran a cover of the cars in a slanted lineup; they could not be singularly identified.

After Mr. Rybicki, the chief design post went to a colorful leader, Charles M. Jordan, in 1986. Among his best efforts were the later Riviera and the most recent vintage Oldsmobile Toronado. He also was responsible for the current Camaro, Firebird and previous-generation Corvette.

Wayne Cherry, the fifth and current chief, took over the design helm in 1992 after a distinguished career in Europe. Mr. Cherry introduced far more electronic technology. He undoubtedly is the most modest of the five design chiefs. His efforts remain to be judged, although GM market share has plunged below 30% in the new century. In Harley Earl's prime, GM accounted for more than half the market and Cadillac completely dominated the luxury section as opposed to its fifth-place ranking among the elite today.

But Mr. Earl's times were completely foreign to the current market where Asian and European competition and federal regulations play key roles. He might have enjoyed greater control over design when Chairman Roger B. Smith (1981-1990) set up a new tier of management over the divisions. One was B-O-C for Buick, Oldsmobile and Cadillac and the other was C-P-C for Chevrolet, Pontiac and Canada. Both those tiers are long gone. Since then, GM has hired brand managers and vehicle line executives in a major revision beginning in the early '90s. The divisions today are sharply reduced in size and are primarily marketing operations. Observes Mr. Moon: “It seems GM is still reorganizing.”