He greatly expanded endowments and the university's engineering school, which has spawned companies such as Google and Yahoo.
Marc Andreessen, the developer of one of the first web browsers and a top Silicon Valley investor has called Hennessy "Godfather of Silicon Valley." He sits on the boards of Google, Cisco Systems, and Atheros Communications.
Hennessy joined the faculty in 1977 just as Silicon Valley was starting. He co-founded MIPS Computer Systems in 1984, a maker of Reduced Instruction Set Computer (RISC) microprocessor chips and acquired for $333 million by Silicon Graphics in 1992.
As President of Stanford University he has raised massive amounts of money, $1.6 billion in 2015 alone, allowing for the expansion of Stanford's engineering school with a brand new quad, and many other buildings.
His engineering credentials and high profile in Silicon Valley's tech community have critics saying that Stanford is now seen as a tech-oriented school and it's humanities schools have suffered.
Under Hennessy Stanford University became the most exclusive and expensive private university in the US. This year less than 5% of nearly 44,000 student applicants were accepted, and its endowment grew to $21.5 billion.
The explosive demand for computer science (CS) Engineers helped fuel a big expansion of the computer science school at Stanford but it won't be enough to supply all the engineers needed by many industries.
In a recent interview in "The Communications of the ACM" Hennessy warned,
We're going to struggle to meet the [CS] demand. All institutions are facing this because CS graduates have lots of good opportunities, both within the academy as well as outside it. We're also going to see other fields begin to change, but change takes a long time. Universities change at a very slow pace getting new faculty.
However, I think we can already see the rise of quantitative empirical analytical approaches, for example take a discipline like political science. The action is in doing big data analysis of elections and surveys. It requires a different kind of expertise and background.
...We're going to see a rise of the influence of big data in the social sciences, and they're going to become more quantitative in how we formulate policy.