He served as a law clerk to Judge Harrison Lee Winter of the United States Court of Appeals for the Fourth Circuit from 1967 to 1968.

[4] In 1999, Motz ruled against Ida Wells, a former secretary for the Democratic National Committee, who had sued G. Gordon Liddy for defamation.

In December 2011, Motz presided at the two-month trial in Salt Lake City of an anti-competition lawsuit where Novell claimed $1 billion from Microsoft.

The issue was Microsoft's discontinuance of a Windows feature that Novell's WordPerfect software depended on; the company argued a theory of cross-market injury.

Microsoft CEO Bill Gates testified on the witness stand for two days in defending his decision during the two-month trial.

On December 16, Judge Motz declared a mistrial due to a hung jury; after three days it had not reached the unanimous decision required.