Financial insiders know him as a successful venture capitalist a man who bet on small tech companies and made millions when they went public.

The rest of Los Angeles knows him as the mayor.

Richard Riordan has worn many hats in his lifetime attorney, leveraged buyout artist, real estate investor and restaurateur among them. But his success as a venture capitalist was most responsible for building his fortune, which in turn allowed him to finance his political career.

Riordan is no longer actively involved in start-up companies; his investments were put into a blind trust when he was elected mayor in order to avoid conflicts of interest.

But as a venture capitalist, his strategy for making successful investments in companies without a long track record was to get to know the company owners personally.

“The thing you do before you invest is really know the management, make your own judgment on management,” Riordan said. “Don’t accept reference calls other people make. Make key reference calls to people likely to tell you the full truth.”

Riordan was most successful as a venture capitalist, he said, when he made an extra effort to get to know company managers on a personal level. “Go out and get drunk with the guy before you invest,” he said.

Riordan stopped being as closely involved in each of his venture capital investments about 15 years ago. “When things started going so well, I got away from that, (and that) is when I started to make some mistakes,” Riordan said, adding that when he stopped getting to know company management personally, his success rate dropped from 80 percent to 50 percent.

Nevertheless, Riordan is considered one of L.A.’s more astute investors.

“Dick Riordan is an excellent venture capitalist who made a lot of money in this city,” said George Sollman, chairman of the American Electronics Association, the nation’s largest high technology trade group. “Riordan made very good money in high tech investments.”

In fact, Riordan, 67, made upwards of $50 million in venture capital investments much of it in technology, an industry he recognized early in his career as potentially lucrative.

In 1956, Riordan, who had just received a law degree from the University of Michigan, took an $80,000 inheritance from his father, split it four ways and invested in Control Data Corp., Litton Technologies Inc., Haloid and Syntex Corp.

“That was a lot of money in those days,” Riordan has said. “I played in the high technology stocks of that era.”

Palo Alto-based Syntex gave Riordan the biggest return on his investment when it began selling the first birth control pills. Riordan’s original $20,000 investment quickly netted him $180,000.

Meanwhile, his investment in the other three companies including Haloid, which later became Xerox Corp. netted him another $180,000. Within just a few years, Riordan, still in his 20s, had $500,000 to his name.

When Riordan moved to L.A. to join the downtown law firm of O’Melveny & Myers, he continued to play the stock market, but quickly shifted his focus to start-ups. His first investment was in one of the first companies to produce low-cost cassette tape cartridges.

Riordan moved from law firm to law firm before co-founding Riordan & McKinzie in 1975. He also put together various investment partnerships, such as the since-disbanded Riordan, Freeman & Spogli in 1983.

Riordan’s first big venture capital success was a $650,000 investment in Santa Clara-based Convergent Technologies Inc., founded by former Intel Corp. executive Alan Michaels to sell computer workstations similar to those made by Sun Microsystems. Riordan’s initial investment grew to $19.9 million when Unisys Corp. acquired Convergent in 1985.

Around that time, Riordan formed the venture capital firm of Riordan, Lewis & Haden now one of the top 15 venture capital firms in L.A. with USC graduate and former pro tennis star J. Christopher Lewis and former L.A. Rams quarterback Pat Haden.

“I met Dick in 1981 at a social occasion, and I was interested in the venture capital business, and I think Dick was looking for someone to mentor,” Lewis said. “Back then, he was a part-time lawyer and a part-time venture capitalist.”

In the early 1980s, when Lewis worked at Riordan, Freeman & Spogli, Riordan focused mostly on computer, medical and semiconductor companies, Lewis said. Many of the companies were start-ups, and some didn’t have revenue yet.

By the mid-’80s, when Riordan and Lewis were investing more of their own money, their focus changed.

“We started to buy much more mature companies, with $10 million to $100 million in revenues, but which have an opportunity to grow at 25 percent a year,” Lewis said.

In the mid-’80s, Riordan also supplemented his venture capital investments with leveraged buyouts, such as the 1984 buyout of Mattel Inc. He also participated in the buyout of several supermarket chains through the ’80s.

When leveraged buyouts started becoming more expensive around 1987, Riordan returned to venture capital as an emphasis.

With Riordan now in office and unable to participate in Riordan, Lewis & Haden’s investments, Haden has been responsible for a blind trust for the mayor.

“This is a unique situation. I can’t tell our main source of capital that we invested in. If we weren’t doing well, it would be a very awkward situation, but since we are doing well, I can be cavalier about it,” Lewis said.

Even with a blind trust, Riordan’s venture capital investment in one company Pasadena-based Tetra Tech Inc. has caused him some trouble.

As a member of the Metropolitan Transportation Authority board, Riordan voted in such a way that the environmental firm received a $1.05-million contract. Riordan said at the time he didn’t know the company would benefit, and later sold his nearly $10 million in Tetra Tech stock.

Riordan, whose fortune is thought to top $125 million, said that he has not decided whether he will return to the world of venture capital full-time after he his termed out of the Mayor’s Office in 2001. But at least one person hopes that he will.

“A lot of people ask me that, and I sure hope he does,” Lewis said.

Staff reporters Benjamin Mark Cole and Ben Sullivan contributed to this article.