He is best known, however, for founding the Zoological Society, which grew out of his involvement with the Panama–California Exposition in 1916, and for being the driving force behind the creation and early growth of the zoo.

He convinced several wealthy San Diegans to contribute to the zoo's construction and development, and campaigned for ballot measures to secure its lands and finances.

After a heart attack in 1931 forced him to abandon his medical practice, he spent his remaining years traveling the world, collecting and trading animals for the zoo.

An amphitheatre at the zoo and an elementary school and day care facility in San Diego's Serra Mesa community are named in his honor.

[4] Harry had twelve siblings: Brothers Arthur, George, Paul, and Charles; sisters Emma and Ellen; and six older half-brothers from his father's previous marriages.

[5][6] Harry showed an interest in animals from childhood, reading books on their habits and characteristics, playing at circus using toy ones, searching for crabs in Chesapeake Bay, and hunting for snakes in nearby woods and then selling them to neighbors.

[10] After contracting influenza during a snowstorm, he diagnosed himself with acute tuberculosis and, on the advice of one of his brothers, moved to Colorado for his respiratory health at age sixteen.

[12] He stopped off in Jamestown, North Dakota, but found the weather too cold and continued on to Seattle, then south, arriving in San Diego.

[12][14] Passing the California State Board of Medicine examinations, he borrowed $50 and opened offices in downtown San Diego in the Granger Building at the southwest corner of D Street (now Broadway) and Fifth Avenue in 1910.

[19] Feeling that mayor James E. Wadham and the San Diego City Council did not back these attempted reforms, he criticized them in newspapers and was promptly fired.

[19] His efforts were lauded in a San Diego Sun editorial, which said "He has worked hard and long and courageously against that old-fossilized regime which has done little or nothing to stop unclean meat, poor milk, and carelessly kept foodstuffs, along with a suspicion of petty graft among the subordinates of the city service ...

[21][22] By his own account, his inspiration came on September 16, 1916, as he and Paul were driving down Sixth Avenue on their way back to their office after performing an operation at the St. Joseph Hospital.

[23] Hearing the roaring of lions from one of the Exposition's exhibits, Harry remarked to his brother "Wouldn't it be splendid if San Diego had a zoo!

[22][23][24] Joined by naturalist Frank Stephens and doctors Fred Baker and Joseph Cheesman Thompson, they held the first organizational meeting of the Zoological Society of San Diego on October 2, 1916 in the Wegeforths' offices; Harry served as the founding president, Paul as secretary.

[30] Upon American entry into World War I in mid-1917, Paul Wegeforth resigned from the Zoological Society's Board of Directors to accept a commission in the United States Army.

[1][22][34][35] Reapplying to the Army Medical Corps, Wegeforth was commissioned as a captain in July 1918 and assigned to the Neuro-Surgical Institute of New York for training.

[22] Wegeforth initially asked the city council for almost ten percent of Balboa Park's 1,200-acres (490 ha) for the zoo, but was rebuffed by parties who believed the acreage should be left as open parkland.

The most prominent was Frank Buck, who went to work as temporary director for the San Diego Zoo on June 13, 1923, signed to a three-year contract by Wegeforth.

[12][17] Their wedding, which was attended by actresses Norma, Natalie, and Constance Talmadge, took place at a new house in the city's Burlingame neighborhood, where the couple lived for a year.

Wegeforth enjoyed cars; he bought a new Overland Automobile around the time of his marriage, and in 1923 went into debt to buy an eight-cylinder, fully equipped Packard which he paid to have repainted fire engine red, then traded in within a year.

[46] His hobbies included building radios, shooting, and photography; he created a large collection of color slides documenting the zoo and his worldwide travels.