Startup Attorney Jon Atzen Switches Firms

Jon Atzen has joined the Los Angeles office of Sheppard, Mullin, Richter & Hampton LLP as a partner focused on emerging companies. He previously was a partner with DLA Piper.


Jon Atzen has joined the Los Angeles/Downtown office of Sheppard, Mullin, Richter & Hampton LLP as a partner in the firm’s Corporate practice group and member of the Emerging Companies practice. Atzen most recently was a partner at DLA Piper in Los Angeles.

Atzen has devoted virtually his entire career to working with leading entrepreneurs and innovators, as well as emerging and established companies, primarily in the southern California region. He focuses his corporate practice on representing emerging growth and established companies, and venture capital and private equity funds, in such technology sectors as life sciences, semiconductors, wireless communications, internet, software and clean/alternative energy technologies.

“Jon has an impressive emerging growth company background, which includes private practice and corporate counsel for both a tech company and a venture capital firm. His practice dovetails well with our existing emerging growth/venture capital practices throughout California, while broadening our existing corporate practice capabilities in Los Angeles,” said Guy N. Halgren, chairman of the firm.

In addition to private practice, Atzen previously held the positions of Senior Vice President, General Counsel and Corporate Secretary at Advanced Cell Technology, Inc.

“I am excited about joining Sheppard Mullin, a top-notch full service firm with a strong corporate practice in Los Angeles and throughout the state,” Atzen commented. “I am impressed with firm management’s dedication to growing the Corporate practice group, and excited to be part of a partnership that values teamwork and fosters collegiality.”

In addition to his venture capital and private equity practice, Atzen provides corporate and strategic counsel to publicly-traded companies with respect to securities offerings including initial public offerings, secondary offerings, PIPEs and spin-offs, and reporting and compliance matters under the Securities Exchange Act of 1934. He also has significant experience in public and private company mergers and acquisitions.

Atzen received a J.D. from Loyola Law School Los Angeles in 1990 and a B.A. from University of California at Santa Barbara in 1987.

Sheppard Mullin has 200 attorneys based in its Los Angeles offices. The firm’s Corporate practice group includes 100 attorneys firmwide.

In April, Kevin Rooney joined the firm’s Silicon Valley office as a partner in the Corporate practice group. Rooney most recently practiced at Hayden Bergman & Rooney in San Francisco, as a name partner. Previously, Rooney was an attorney with Wilson Sonsini in Palo Alto and Davies Ward Phillips & Vineburg in Toronto.

About Sheppard, Mullin, Richter & Hampton LLP
Sheppard Mullin is a full service AmLaw 100 firm with 550 attorneys in 11 offices located in the United States and Asia. Since 1927, companies have turned to Sheppard Mullin to handle corporate and technology matters, high stakes litigation and complex financial transactions. In the U.S., the firm’s clients include more than half of the Fortune 100. For more information, please visit