Mossimo specialized in youth and teenage clothing such as shirts, jeans, jackets, socks, underwear, and accessories.

Giannulli dropped out of the University of Southern California in 1987, to create his Mossimo streetwear line, with a $100,000 loan from his father.

[1] At the close of his company's first fiscal year, Giannulli had $1 million in profits.

On March 28, 2000, Mossimo, Inc announced a major, multi-product licensing agreement with Target stores, for $27.8 million.

[7] Mossimo and his wife, actress Lori Loughlin, were convicted of bribing University of Southern California officials with up to $500,000, to secure enrollment of their two daughters.