Jöreskog is a professor emeritus at Uppsala University, and a co-author (with Dag Sörbom) of the LISREL statistical program.
He was a statistician at Educational Testing Service (ETS) and a visiting professor at Princeton University.
Jöreskog proposed a reliable numerical method for computing maximum-likelihood estimates in factor analysis; similarly reliable methods were also proposed by Gerhard Derflinger, Robert Jennrich, and Stephen M. Robinson at roughly the same time.
While working at the Educational Testing Service and giving lectures at Princeton University, Jöreskog proposed a linear model for the analysis of covariance structures, a fundamental contribution to structural equation modeling (SEM).
His other research interests include multivariate analysis, item response theory, statistical computing, and factor-analysis in geology.