[2]: 4 [3] A 2006 study of del Valle headed by David E. Hayes-Bautista[4] reported that: "Young Reginaldo was tutored at home, becoming fluent in English and French as well as Spanish."

He read law with the San Francisco firm of Winans and Belknap, and he passed the state bar examination in 1877.

[2]: 29 He died on September 20, 1938, leaving daughter Lucretia Grady and a sister, Josefa del Valle Forster.

[2]: 5, 7 While an Assemblyman, del Valle received a letter from former Governor John G. Downey, dated February 22, 1879, encouraging him to "push for a Los Angeles location" for a new state normal school, which would specialize in teacher training.

As a result, according to a history of the Los Angeles State Normal School written twenty-five years later, "Mr. Del Valle became a target for the Workingman's Delegation of San Francisco, some members of which in the heat of the debate made use of sharp personalities.

[2]: 20 [3] In the latter year, the Los Angeles Times noted that del Valle: is the parliamentarian par excellence in the upper House.

Since his school days at Santa Clara College, he is generally accredited with having adopted Cushing's unabridged, so to say, as his Bible.

He also was "one of the forty founding members of the Southern California Historical Society and spearheaded the committee to restore the San Fernando Mission and the mark El Camino Real with bells.