Jobs had a hand in making event loops standard programming fare, and was there when Apple and NeXT pushed languages such as Objective-C and Dylan and various software frameworks, and decided to cease supporting others. -
http://lambda-the-ultimate.org/node/4372I can't find the link but I also read about Jobs going on a tirade to his employees about some aspect of Objective-C while at Apple.
Another case supporting him as a technical cofounder(although not a programmer) is when he worked at Atari on 'Breakout'. From wikipedia: "The same year, Alcorn assigned Steve Jobs to design a prototype. Jobs was offered US$750, with an extra $100 each time a chip was eliminated from the prospected design. Jobs promised to complete a prototype within four days. Jobs noticed his friend Steve Wozniak—employee of Hewlett-Packard—was capable of producing designs with a small number of chips, and invited him to work on the hardware."
Jobs may not have done the job himself but he was clearly working in a technical position at the time.