John Langford
Partner Researcher Manager at Microsoft Research; principal developer of Vowpal Wabbit
- Partner Researcher Manager, Microsoft Research21
John Langford is a machine learning researcher at Microsoft Research, credited as Partner Researcher Manager on the March 2026 Microsoft Research post about Phi-4-reasoning-vision-15B, of whose technical report Langford is a co-author. Langford's Microsoft Research page describes Langford as the principal developer of the Vowpal Wabbit learning system and the primary author of the machine learning weblog hunch.net, with earlier research projects including Isomap, Captcha, learning reductions, cover trees and contextual bandit learning.231
Career
Langford earned a double bachelor's degree in physics and computer science at the California Institute of Technology in 1997 and a PhD at Carnegie Mellon University in 2002. Langford's page lists later work at Yahoo!, the Toyota Technological Institute and IBM's Watson Research Center, and Langford is now at Microsoft Research.1
Research
Langford's research projects include Isomap, Captcha, learning reductions, cover trees and contextual bandit learning, and Langford is the principal developer of Vowpal Wabbit and primary author of the hunch.net weblog. Langford is among the six authors of the Phi-4-reasoning-vision-15B technical report, a compact multimodal reasoning model released by Microsoft in 2026.132
Work
Phi-4-reasoning-vision-15BOpen weights
Co-author of the Phi-4-reasoning-vision-15B technical report and of the Microsoft Research post on lessons from training the model.23
Vowpal Wabbit (external site: github.com)Open-source code
Principal developer of the Vowpal Wabbit machine learning system, according to Langford's Microsoft Research page.1
Career timeline
Other documented roles
Roles the sources document but that are not confirmed as current.
- Research roles after 2002 (past), Yahoo!, Toyota Technological Institute and IBM Watson Research Center1
Related people
More sourced profiles at the same organization, in the same field, or from the same school.
- Adam FourneyAlso at Microsoft Research
- Jeff CluneReinforcement learning
- Albert GuAlso from Carnegie Mellon
- Andreas C. MüllerAlso at Microsoft
- Kenneth StanleyReinforcement learning
- Alex SmolaAlso from Carnegie Mellon
- Bin XiaoAlso at Microsoft
- Abhimanyu DasAlso at Microsoft Research
- Alexei A. EfrosAlso from Carnegie Mellon
- Charles LamannaAlso at Microsoft
- Adam GleaveReinforcement learning
- Ali FarhadiAlso from Carnegie Mellon
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