|Born||1936 (age 79–80)|
|Residence||Palo Alto, California|
|Net worth||US $ 2.3 billion (June 2015)'|
|Children||John Arrillaga, Jr., Laura Arrillaga-Andreessen(Daughter), Marc Andreessen (son-in-law)|
John Arrillaga Sr is one of five children in a lower-middle-class home to his father Gabriel, who traced his roots to the Basque region and mother Freida. He attended Morningside High School in Inglewood, California and graduated in 1955. He attended Stanford University on a basketball scholarship, and was a first-team All-AAWU selection in 1960. He graduated with a bachelor's degree in geography (no longer offered) in 1960, where he was a member of Delta Tau Delta.
In the 1960s, Arrillaga and business partner Richard Peery bought California farmland and converted it into office space. They became two of Silicon Valley's biggest commercial landlords with more than 12,000,000 square feet (1,100,000 m2).
In 2006, he sold 5,300,000 sq ft (490,000 m2) of his real estate holdings for roughly $1.1 billion.
He is well known for his generous support of Stanford University. The alumni center, the Frances C. Arrillaga Building, is named in memory of his first wife, and various other athletic facilities carry his surname. In May 2006, Arrillaga gave $100 million to Stanford.
In June 2013, he again donated to Stanford, writing a check for $151 million, making it the largest individual donation in the school's history.
Arrillaga is widowed, and is remarried to Gioia Fasi Arrillaga. The couple resides in Portola Valley, California. His daughter Laura Arrillaga-Andreessen is married to Marc Andreessen, the successful entrepreneur who co-authored the Mosaic and Netscape web browsers, and who is co-founder of several web technology enterprises. His son John Arrillaga, Jr. is married to Justine Stamen Arrillaga, founder of the TEAK Fellowship.
- "The World's Billionaires: #719 John Arrillaga". Forbes. March 2012.
- The secretive billionaire who built Silicon Valley 2014
- "Basque Studies Debut" (March/April 2007) Stanford Magazine. Retrieved 05 June 2010.
- "Forbes World's Richest People 2003". Forbes. 2003.
- Fainaru-Wada, Mark (2001-02-25). "Silent Partner / Billionaire Arrillaga has quietly been the primary benefactor behind Stanford's athletic success". San Francisco Chronicle.
- "Arrillaga gives $100 million to Stanford in largest single gift ever from individual". Stanford Report. May 26, 2006.
- Stangel, Luke. "John Arrillaga writes $150 million check to Stanford, the largest donation from a living individual ever". Silicon Valley Business Journal. Retrieved 1 July 2013.
- "2012 In-Kind Gifts & Special Thanks". TEAK Fellowship. Retrieved 9 October 2014.