Born in Alliance, Ohio on November 9, 1949, Sag attended the Mercersburg Academy but was expelled shortly before graduation. He received a BA from the University of Rochester, an MA from the University of Pennsylvania, where he studied comparative Indo-European languages, Sanskrit, and sociolinguistics, and a PhD from MIT in 1976, writing his dissertation (advised by Noam Chomsky) on ellipsis.
Sag was the Sadie Dernham Patek Professor in Humanities, Professor of Linguistics, and Director of the Symbolic Systems Program at Stanford University. A fellow of the American Academy of Arts and Sciences and the Linguistic Society of America, in 2005 he received the LSA's Fromkin Prize for distinguished contributions to the field of linguistics.
Sag made notable contributions to the fields of syntax, semantics, pragmatics, and language processing.
His early work was as a member of the research teams that invented and developed HPSG as well as generalized phrase structure grammar, HPSG's immediate intellectual predecessor. More recently, he worked on Sign-Based Construction Grammar, which blended HPSG with ideas from Berkeley Construction Grammar. In general, his research late in life primarily concerned constraint-based, lexicalist models of grammar, and their relation to theories of language processing.
He was the author or co-author of 10 books and over 100 articles.
He was honored by a volume of studies published in 2013 in his honor, The Core and the Periphery: Data-Driven Perspectives on Syntax Inspired by Ivan A. Sag, edited by Philip Hofmeister and Elisabeth Norcliffe.
- Sag, Ivan A. 1980. Deletion and Logical Form. New York:Garland Press.
- Gazdar, Gerald, Ewan Klein, Geoffrey K. Pullum, and Ivan A. Sag. 1985. Generalized Phrase Structure Grammar. Cambridge, MA: Harvard University Press and Oxford: Basil Blackwell’s.
- Sag, Ivan A., Gerald Gazdar, Thomas Wasow and Steven Weisler. 1985. "Coordination and How to Distinguish Categories." Natural Language and Linguistic Theory 3:117–171
- Pollard, Carl, and Ivan A. Sag. 1987. Information-Based Syntax and Semantics; Volume One - Fundamentals. CSLI Lecture Notes Series No. 13. Stanford: CSLI Publications. Distributed by University of Chicago Press.
- Nunberg, Geoffrey, Ivan A. Sag, and Thomas Wasow. 1994. "Idioms." Language 70:491– 538.
- Pollard, Carl, and Ivan A. Sag. 1992. "Anaphors in English and the Scope of Binding Theory." Linguistic Inquiry 23.2:261–303.
- Pollard, Carl, and Ivan A. Sag. 1994. Head-Driven Phrase Structure Grammar. Chicago: University of Chicago Press and Stanford: CSLI Publications.
- Miller, Philip, and Ivan A. Sag. 1997. "French Clitic Movement Without Clitics or Movement." Natural Language and Linguistic Theory 15:573–639.
- Sag, Ivan A. 1997. "English Relative Clause Constructions." Journal of Linguistics 33.2:431–484.
- Jonathan Ginzburg and Ivan A. Sag. 2000. Interrogative Investigations: the form, meaning, and use of English Interrogatives. Stanford: CSLI Publications.
- Bouma, Gosse, Robert Malouf, and Ivan A. Sag. 2001. "Satisfying Constraints on Extraction and Adjunction." Natural Language and Linguistic Theory 19.1:1–65.
- Kim, Jong-Bok, and Ivan A. Sag. 2002. "French and English Negation without Head-Movement." Natural Language and Linguistic Theory 20.2:339-412.
- Sag, Ivan A., Thomas Wasow, and Emily Bender. Syntactic Theory: A formal introduction. Second edition. Stanford: CSLI Publications.
- "Ivan A. Sag". Stanford University.
- "RIP Ivan Sag (1949-2013)". Stanford University Symbolic Systems Program.
- Goldman, Corrie (September 27, 2013). "Stanford Linguistics Professor and Cognitive Scientist Ivan Sag Dies at 63". Stanford News.
- Symbolic Systems Program
- "LSA Honors and Awards". Linguistic Society of America. Retrieved Sep 2013.