Chaals' first IT accessibility job was in the 1980s. From 1998 to 2003 he was a member of staff at the W3C's Web Accessibility Initiative, and for more than 20 years accessibility has been something he has made a part of his job because it is one of the aspects of development that professionals expect to be done right. (It's also true that otherwise, his friends would nag him about it).

He has worked on WCAG from the initial stages of what became WCAG 1.0 to the current "Silver" project for a next generation of accessibility guidelines, as well as the lesser-known but very valuable Authoring Tool Accessibility Guidelines, among a broad range of W3C accessibility work. He has worked on other accessibility projects ranging from ISO work to testing and reporting on the accessibility of individual web pages, which has put him in almost every different position there is in the world of accessibility.

Since working at W3C he spent some years as head of standards at Opera Software and as a consultant to the CTO of Yandex, and is currently employed by Consensys Systems, who have seconded him to work as Technical Program Director for the Enterprise Ethereum Alliance among other responsibilities.