One of the "most conspicuous Southern Californians of his generation",[1] Widney was a cultural leader in Los Angeles for nearly seventy years.

[3] After graduating from Piqua High School, he entered Miami University at Oxford, Ohio where, for five months, he studied Latin, Greek, and the classics.

[4] With the encouragement of his two older brothers and his uncle, Charles Maclay, in California, Widney sailed to San Francisco via Panama, arriving in November 1862.

He was posted to Drum Barracks[9] in Wilmington, California, for a month in 1867, and was named Acting Assistant Surgeon for the Arizona Territory during the Apache Wars.

[15] On May 12, 1937, a bust of Widney commissioned by the Los Angeles County Medical Association was placed in the lobby of their headquarters.

In 1886, he helped establish the Southern California Practitioner, the society's monthly journal, and served as an editor for the first few years.

Widney credited white settlement with improvements in the Southern California climate, including less variation in temperature, milder winds, and increased rainfall.

His brother, Robert Maclay Widney (1838–1929), had arrived in Los Angeles in 1868, and was a lawyer, and later judge, as well as the city's first real estate agent.

Joseph Widney invested in real estate in the Los Angeles area, which made him financially independent, and allowed him to retire from the practice of medicine at 55.

[33] Horace Bell, in his On the Old West Coast, a personal reflection on that period, critiqued the boomers, as a "speculative conspiracy against all that was honest."

"[34] The Los Angeles Times of June 2, 1887 said that Widney had purchased a hotel and several bath houses in the town of Iron-Sulphur Springs, once known as Fulton Wells and now as Santa Fe Springs, fifteen miles (24 km) east of downtown Los Angeles.

To develop Los Angeles, Widney proposed roads and tunnels to cross the Sierra Madre Mountains, linking the city and the interior desert.

[38]Jaher lists Widney as among those Los Angeles entrepreneurs who were the "most avid civic boosters ... [who] made sanguine by their triumphs, they expect urban growth to bring further gains ... [who] predicted that the city would become a great metropolis".

In California of the South (1888), described by David Fine as "one of the earliest booster tracts"[41] Widney and Walter Lindley wrote: "The health-seeker who, after suffering in both mind and body, after vainly trying the cold climate of Minnesota and the warm climate of Florida, after visiting Mentone, Cannes, and Nice, after traveling to Cuba and Algiers, and noticing that he is losing ounce upon ounce of flesh, and his cheeks have grown more sunken, his appetite more capricious, his breath more hurried, that his temperature is no longer normal, ... turns with a gleam of hope toward the Occident" – by which they meant Southern California.

He successfully opposed the attempt of the railroad interests of Collis Potter Huntington and his partners from claiming the state tidelands of the harbor for their own purposes, ensuring these lands remained in public hands.

[46] He indicated in 1880 that "the topography, geography, climatic and commercial laws all work for the separation of California into two distinct civil organizations".

[52] He was involved in the University of Southern California from its conception in 1879, and served as a member of the Board of Trustees of USC from 1880 to 1895.

According to Michael Carter, "the University Catalogue for the academic year 1884–85 declared that applicants to the medical school, as to the rest of USC, would not be denied admission because of 'race, color, religion or sex.'"

After he "recognized a call of the Lord",[53] he accepted the presidency at a difficult time in the history of the young institution, which had only twenty-five undergraduate students with a focus on providing secondary education.

He first set up a separate governing board for the College of Liberal Arts, both to refinance the debt and of tying that branch of the institution more closely to California Methodism.

By the time of the annual conference of 1894, the university had passed through its financial crisis, and Widney's principal work was done".

The board finally accepted the resignation, after their benefactor had turned aside repeated requests that he reconsider his decision.

[58] In addition to his responsibilities at USC, Widney served several years as a member and president of the Los Angeles Board of Education.

[56] In October 1894 at the dedication of the Peniel Hall, Widney announced his intention to organize a Training Institute, in which Bible and practical nursing were to be the principal studies.

[61] In the Los Angeles First Methodist Episcopal Church, the Widneys were members of the "District Aid Committee," an organization devoted to securing better support for underpaid pastors.

Widney was influenced by the teachings of preacher David Swing and Thomas Starr King, a broad-minded, religiously inclusive Unitarian minister.

Du Bois used Widney's Race Life of the Aryan Peoples to support his own view of the significance of the contributions of blacks to the development of modern civilization.

Widney wrote "They [the Negroes] once occupied a much wider territory and wielded a vastly greater influence upon earth than they do now.

[78][79][80] The University of Southern California honors its distinguished graduates by presenting the Widney Alumni Award.

His portrait was painted by American artist Orpha Mae Klinker,[81] and a bust of Widney was sculpted by Emil Seletz.