Jack, in addition to founding THQ, also founded LJN and JAKKS Pacific.
JAKKS Pacific CEO, Stephen Berman:
"Jack was a legendary toymaker and a real titan in our industry. He dedicated his talents to JAKKS Pacific for 15 years, and he will be sorely missed."
Jack retired some time ago to spend more quality time with his family, but was hospitalized for several weeks before his death in early May.
Source: THQ Founder Jack Friedman Has Died [1UP]