I made years ago a presentation about Lisp on the Mac:

http://www.music.mcgill.ca/~ferguson/Lisp%20Docs/lisp-and-ma...

Generally the influence of Lisp on Apple was starting in the mid 80s. There were Lisps available for the Apple II, but they did not have much impact.

But a few highlights from the mid 80s on:

Coral developed a Lisp for the Macintosh. See for example:

http://basalgangster.macgui.com/RetroMacComputing/The_Long_V...

and

https://ccl.clozure.com/history.html

Coral Lisp was developed into a Common Lisp and marketed under the name 'Macintosh Allegro Common Lisp' (MACL).

At some point MACL was bought by Apple. Why did Apple buy it? Well MCL was becoming popular at Apple and specifically at their research lab called the 'Advanced Technology Group' (ATG). A lot of ATG projects were Lisp-based. Lisp was used to develop a multimedia development tool called Sk8 (which was used in probably hundred projects with universities) - Sk8 had a scripting language called Sk8script, which was the model for AppleScript. So Apple used MCL for a bunch of research and production applications.

But the biggest reason for buying MCL and its development team was that Apple at that time was working a portable computers: tablet computers and small PDAs. Apple was developing a new Lisp dialect for that (Ralph, later renamed to Dylan) and had written an OS for and with it. The development environment was MCL and the later target were ARM-based tablets and PDAs running Dylan. For some reason (like not enough RAM on the production models) it was decided to write a new OS in C++ and Newtonscript - and another small group worked on a Lisp/Dylan based OS.

Apple later published a Technology Preview of their Dylan system for the Mac.

The first NewtonScript IDE was also written in Lisp. The production version was then written in C++. This was sometimes a strategy: write a prototype application in Lisp (with Mac UI) and then rewrite it in C++ for publication.

One of the main technologists at Apple was Larry Tesler (who came from Xerox) and he was a big user/promoter of Lisp technology at Apple - and he was responsible for the Newton project at some point. https://en.wikipedia.org/wiki/Larry_Tesler

One of the ideas for further research was the Knowledge Navigator: https://www.youtube.com/watch?v=p1goCh3Qd7M

Larry has written about Lisp at Apple:
http://lispm.de/docs/prefix-dylan/book.annotated/foreword.ht...

See also why Lisp was thought as a good base for their application/systems development for PDAs and even the Mac:

http://lispm.de/docs/prefix-dylan/book.annotated/preface.htm...

Apple also collaborated with Lisp Machine companies like Symbolics and TI. They developed Lisp processor boards for the Mac II and made it possible to run a separate Lisp OS in a Mac II. Symbolics for example also made a promo video for Apple and they used a bunch of Macs with their Lisp boards + their graphics software for it.

One of the most important influences came a bit later. A french developer had written the first interactive user interface designer - called SOS Interface - he used LeLisp on a Mac for that. This UI designer was later ported to other Lisps on the Mac and even to Lisp Machines running in a Mac II. At one point Steve Jobs got a demo of this interface designer. He hired the developer (JM Hullot) and it was rewritten as the Interface Designer for NeXT and later Mac OS X. The Interface Designer was one of the most important development tools and maybe still is - it is still a part of XCode.

Lisp at Apple mostly died when Steve Jobs closed the ATG group. He also closed the Newton group. The most important reasons were focussing on the Mac and cost cutting.

https://en.wikipedia.org/wiki/Apple_Advanced_Technology_Grou...