The San Diego Mandolin Orchestra was co-founded in 1968 by Victor DeGuide, who had played viola with the San Diego Symphony and taught music in local schools. With several adult students, he originally called his group the Singing Strings, performing around town at Seaport Village, Balboa Park, and elsewhere.
In 1972, DeGuide was joined by retiring teacher Eugene Vacher and Vacher's pianist/mandolinist wife Mary. Coronado teacher Jim Trepasso (trumpet, piano, mandolin) joined in 1977, and the orchestra has maintained a steady performance schedule ever since. Other members include Ted Scafidi, Theresa Cooper, and Bill Lee.
In 2003, the San Diego Mandolin Orchestra brought the Classical Mandolin Society of America Convention to San Diego, reportedly the biggest mandolin player convention in the U.S.