As he often told the story, George J. Laurer was keeping close watch when his boss returned home from vacation one Sunday afternoon in 1972. Mr. Laurer, who lived across the street in Raleigh, N.C., bounded out to greet him. “I didn’t do what you asked,” he said.

Any confusion on his boss’s part evaporated when Mr. Laurer, a veteran IBM electrical engineer, explained that he had made a breakthrough. The company was working to develop a bar-code and scanner system that could be used in supermarkets across the country to track inventory and speed up checkout lines, and Mr. Laurer had been assigned to work on a proposal for grocery executives.

The bar-code concept had originated in the 1940s, when N. Joseph Woodland designed a bull’s eye-shaped system of concentric circles, inspired by the dots and dashes of Morse code. It took decades for computing and laster technologies to catch up to his vision, but Woodland was now an IBM colleague of Mr. Laurer, who had been instructed to develop the bull’s eye system for commercial use.

Mr. Laurer decided that the Woodland approach was fatally flawed — too large, and prone to printing problems. “When you run a circle through a high-speed press, there are parts that are going to get smeared,” he told the New York Times in 2013. “So I came up with my own code.”

The result, a zebralike pattern of vertical black lines, became the basis for the modern bar code — the Universal Product Code — which shook up everything from retail to air travel, marathon races to medical devices. A staple of soup cans, sports cars and most everything else that is sold in stores, UPCs are scanned more than 6 billion times each day, according to GS1, a nonprofit organization that manages and issues the codes.

Its proliferation and enduring use surprised even Mr. Lauer, who was 94 when he died Dec. 5 at his home in Wendell, N.C. He had prostate cancer and a heart ailment, said his son Craig Laurer, and was still tinkering up until his death, working to make his hospital bed more comfortable and using timer-controlled lamps so that his clock glowed blue or red depending on the time of day.

As with so many other inventions, the UPC was less the creation of a solitary genius than the work of a small group of collaborators. Primary credit is generally given to Woodland, who said he developed his bull’s eye concept while running his hands through the sand at Miami Beach, forming thick lines with his fingers.

He and another inventor, Bernard Silver, patented an early version of their system in 1952, and Woodland later received the National Medal of Technology from President George H.W. Bush. Mr. Laurer called him “the father of the supermarket scanning system.”

While bar codes were occasionally used by companies in the 1960s, there was no standardized system, and nothing cheap, reliable or small enough for regular use at grocery stores, where cashiers punched keys to enter the price of each item by hand. A group of executives formed a search committee to solve that problem in the early 1970s, taking bids from companies including IBM and RCA.

Mr. Laurer recalled that on the day he presented his rectangular bar-code proposal, his boss “made it clear that if I was wrong or if I could not sell the idea to the brass it would end my career, not his.

“I was truly playing ‘bet your job’ by designing a new code and symbol rather than supporting what the brass wanted,” he continued, according to an IBM history. “My arguments must have been persuasive.”

Mr. Laurer refined his design with colleagues including Heard Baumeister and Woodland, who wrote the final proposal adopted by the grocery industry in 1973. The standard UPC still usually consists of a 12-digit number, as well as 30 black bars (and 29 light spaces) that convey 95 bits of data in binary code, enabling a scanner to look up information in a database.

In 1974, UPCs were used commercially for the first time, when a Marsh Supermarkets executive bought a 10-pack of Wrigley’s Juicy Fruit gum at a store in Troy, Ohio, for 67 cents. The system had by then undergone rigorous, if rather un­or­tho­dox, testing, to demonstrate that bar codes could be read on most any product, scanned at just about any speed.

“Before we showed it to the public, IBM printed the symbol on the bottom of one of those beanbag ashtrays, then had an ace softball pitcher throw it past the scanner as fast as he could,” Mr. Laurer told the Charlotte Observer in 1998. “The scanner read it. It was only then that the division head said, ‘I think this will work.’ ”

George Laurer was born in New York City on Sept. 23, 1925. (His middle name, Joseph, was apparently added later.) His mother ran a children’s day care, and his father was a lawyer who became an electrical engineer, moving the family to Baltimore to work for the Navy.

Mr. Laurer tinkered with radios and model airplanes from a young age, building small wooden outrigger boats out of fruit baskets to sail at a local park. Bedridden with polio for about two years as a teenager, he recovered only to be drafted into the Army while still a junior in high school, according to his family.

He served stateside during World War II and returned home to study electronics repair at a Baltimore technical school, where an instructor encouraged him to obtain a high school equivalency diploma and attend college. Mr. Laurer received a bachelor’s degree in electrical engineering from the University of Maryland in 1951.

He joined IBM in Endicott, N.Y., later that year and remained at the company for 36 years, working out of its Research Triangle Park offices in North Carolina beginning in the late 1960s. He received more than two dozen patents and spent much of his career developing bar-code sensors, which he said had driven IBM’s interest in the technology in the first place. The company never patented UPC, he told the Observer, and “just gave the symbol away as a way to sell equipment.”

Mr. Laurer’s wife of 59 years, Marilyn Slocum Laurer, died in 2013. In addition to his son Craig, of Danbury, Conn., survivors include three other children, Debra Laurer Cook of Clayton, N.C., Mark Laurer of Lexington, Ky., and Jonathan Laurer of Raleigh; three grandchildren; and three great-grandchildren.

In interviews, Mr. Laurer sometimes noted that he never received royalties or grew wealthy from UPC, which saved the grocery industry an estimated $17 billion in the quarter-century after its creation. Instead, he said, he was met by a steady stream of conspiracy theorists, who believed he had encoded the devilish number 666 inside the UPC, through the placement of three long “guard bars” that mark the beginning, middle and end of each code.

“I didn’t get the meat,” he lamented in a 2013 interview with the Times, “but I did get the nuts.”