The Trippet Ranch gate of Topanga State Park is named for him, as his family owned the land through the first half of the 20th century.

He was confirmed by the United States Senate on March 3, 1915, and received his commission the same day.

[11] Also in 1919 he sentenced millionaire Hulett C. Merritt of Pasadena to five months in jail and a $5,000 fine for hoarding sugar in violation of wartime food restrictions.

[12] In 1920 he ruled that boxer Jack Johnson should be transported to Chicago from Los Angeles to face outstanding "white slavery" charges there.

[8] Over Fourth of July weekend in 1892 Trippet was accidentally shot in the face by a friend during a hunting trip near Viejas Valley, California.

[16] The cause of Judge Trippet's death was heart attack; he died during a weekend visit to a second home in Lake Arrowhead, San Bernardino, California.

[20] Trippet's son Oscar Trippet Jr. was a Stanford-educated lawyer who was involved in promoting the development of Los Angeles and civic organizations including the Hollywood Bowl Association and the Los Angeles Chamber of Commerce.