Anyone who uses the cut, copy and paste commands on their computer or mobile device has Larry Tesler to thank for making them so simple and easy to use.

Tesler, who has died aged 74, began his work on cut, copy and paste in 1973, when he was hired by Xerox’s Palo Alto Research Center (Parc) in California. Among other things he worked with a fellow computer scientist, Tim Mott, on the development of Gypsy, a “modeless” word processor. At the time most software had modes: for example, you might press I to enter the insert mode, or R for the replace mode. But Tesler’s research showed that non-expert users found modes confusing – and so he began to fight against them. He had “Nomodes” as his car numberplate and, later, a website at nomodes.com.

Although Tesler did not actually invent the basic functions of cut, copy and paste, he did come up with the names, keystroke combinations (Ctrl-X, Ctrl-C, Ctrl-V) and definitions for a simpler, modeless regime that became universal. As such he was happy to describe himself as the “primary inventor of modeless editing and cut, copy, paste”. It was a proud achievement, for his invention seems likely to survive for as long as there are real or virtual keyboards.

Tesler was also known for demonstrating Parc’s graphical user interface to Apple’s co-founder, Steve Jobs. In computer mythology this is said to have inspired the creation of the Apple Lisa and Macintosh computers in the early 1980s. Later, when working at Apple, he also played a significant role in the commercial success of the ARM (Acorn Risc Machine) processor, which today powers the vast majority of smartphones and tablets.

Tesler was born in New York, to Isidore Tesler, an anaesthetist, and his wife, Muriel (nee Krechmer). While attending the Bronx high school of science in the early 60s, he came up with an algorithm for generating prime numbers. A teacher told him it could be implemented on a computer, and found him a machine language manual for the IBM 650 mainframe. When given time on an IBM 650 at Columbia University – half an hour every other Saturday – he tried to run his algorithm from a deck of punched cards, but the computer was too difficult to use. It was a problem he would spend the rest of his life trying to mitigate.

After school Tesler went to Stanford University in Palo Alto, mainly to get away from his parents. “They were kind of constraining and over-controlling and I was just too free-spirited for that,” he said. It turned out to be a brilliant decision. Silicon Valley was propagating a new computer industry and an anti-war counterculture.

Facebook Twitter Pinterest Larry Tesler using an early Xerox Parc Alto personal computer system in the 1970s. Photograph: AP

Tesler threw himself into both. He was soon being paid to write software for various university departments, and set up a successful consulting company. After he graduated with a maths degree in 1965, his clients included two of the most important organisations in the area: the Stanford Artificial Intelligence Lab, where he wrote Pub, a text-based publishing system, and the Stanford Research Institute, where Doug Engelbart invented the mouse.

Just when everything seemed to be going well, however, the US economy went into recession and business dried up. Tesler was now, after a short marriage that ended in divorce, a single parent with a daughter, Lisa. He did the countercultural thing, dropping out to live in a commune in rural Oregon.

In 1970 Xerox had founded Parc in his old Palo Alto stomping ground. They had been recommended to hire him, but could not find him. When they did, he was the first person ever to turn them down – “I was insulted by the amount of the offer,” he said – and it was not until 1973 that Tesler joined them to work with Mott on the development of a modeless word processor. Thereafter his work on cut, copy and paste brought the concept into the mainstream.

Parc’s researchers also created the first modern computing system with a graphical user interface, icons, a mouse, laser printer and ethernet networking. However, Xerox knew they would never be able to turn these high-priced workstations into mass-market products. That is why they wanted to work with Apple. But when Tesler made his presentation, Jobs and his staff at Apple asked such smart questions that he decided to leave Parc to join the upstart computer company. He served in many positions at Apple from 1980 to 1997, rising to be chief scientist.

In computing circles he was well known for his role in helping to progress the ARM processor from local curiosity to global ubiquity. He had been running Apple’s advanced technology research group when, in 1990, he was asked to take over the company’s beleaguered Newton project. Some people saw small, pen-operated “personal digital assistants” as the next big thing, and the Newton was Apple’s version. Unfortunately it was too big, too slow, too expensive, and looked as if it would never be finished.

Tesler decided that Apple needed a powerful but cheap and battery-friendly processor to make the Newton a viable commercial proposition.He found one in the ARM, which had been developed by Acorn in Cambridge for its Archimedes computer. Apple felt it could not rely on a small British supplier for such an important part, so Tesler set up a three-way joint venture company with Acorn and Acorn’s chip manufacturer, VLSI Technology, to develop and license it.

Tesler was a board director of ARM Ltd when it was founded in 1990, then of ARM Holdings plc until 2004. The Newton flopped and Jobs killed it in 1997, but ARM went from strength to strength.

Not everything that Tesler touched turned to gold. One of his final tasks before leaving Apple was to shut down its advanced technology group and kill off any projects that the company could no longer afford. As part of that process he hived off an Apple educational program, Stagecast Creator, which could be used to teach children a kind of programming, into a start-up business, Stagecast, in which he invested heavily and took on the role of president. The venture was a failure, and he lost a lot of money as a result, which forced him to take on various jobs – including with Amazon, Yahoo and 23andMe – which focused on user experience and interface design. Eventually he became what he called a “semi-retired” consultant.

In an industry where screaming at people used to pass for entrepreneurial zeal, Tesler stood out by being humble and unfailingly nice. When he visited me at the Guardian in the late 1990s to talk about ARM, for example, he did not arrive in a limo, did not bring any flunkies, and did not lay down any terms or conditions. He just turned up on time, had a coffee in the canteen, and later let me walk him to the tube. If he had been less nice, then he would not have spent so much of his career sorting out other people’s messes. But then he also would not be remembered so fondly by so many people.

He is survived by Lisa, by his second wife, the geophysicist Colleen Barton, and by his brothers, Charles and Alan.

• Lawrence Gordon Tesler, computer scientist, born 24 April 1945; died 16 February 2020