[2] When William was seven years old, the family moved to Sanborton Bridge, New Hampshire, where he was educated in the local public schools and an academy.

[2] Ladd received several promotions and was briefly in charge of the company's freight department before being returned to Sanborton Bridge.

[2][3] Disillusioned with the demotion, and spurred by reports from Samuel R. Thurston and a local shopkeeper who had returned with a large fortune, he decided to move west to work with Charles E. Tilton, a former classmate, who was involved in a mercantile business in San Francisco.

[2][3][4] Ladd left from New York City on February 27, 1851, and sailed to San Francisco, traveling over the Isthmus of Panama.

[3] Tilton refused, due to the risk involved, so Ladd traveled north to Oregon on his own.

[3] The day after arriving in Portland, Ladd rented a small store at 42 Front Street and sent an order to Tilton for more liquor.

[3] Ladd only grossed $41.40 in the last two weeks of April and was unable to pay the $6 property tax, instead exchanging several nights and mornings to remove two stumps from the street in lieu of payment.

[3] Early May proved better for Ladd, selling a large amount of gin to Barrell, adding the local Skidmore's California House hotel and Ainsworth's Lot Whitcomb steamer as customers.

[3] He then earned $250 by selling goods from W. D. Gookin on consignment, adding shaving soap, tobacco, paper, farm tools, blasting powder to his store.

[2] William S. Ladd handled the wholesale trade, and 'Sim', Simeon Reed was "the best dressed bartender in early day Portland.

[8] MacColl states that Ladd was equally generous and miserly, a conservative investor, and an adventurous and speculative trader.

"[5] William Ladd and Simeon Reed would also partner in a variety of ventures, including a hobby farm where Reedville, Oregon now stands.

In 1854 William arranged for his bride-to-be, Caroline Ames Elliott (March 18, 1827 – October 23, 1909), with whom he had fallen in love back in New Hampshire,[2] to travel to San Francisco.

William and Caroline had five children surviving into adulthood: (Myra Tilton Ladd (1865–1865) died as infant.

[16] Ladd enthusiastically supported his wife Caroline's educational, charitable, and religious works and credited his success in life to her cooperation and sympathy.

[17] Among her many charitable contributions she donated money to build the first purpose-built Portland Art Museum on land left for that purpose with a bequest from her husband's business associate Henry W. Corbett, her daughter Helen's father-in-law.

[g] Ladd built his house and landscaped the grounds occupying the Portland city block bounded by what is now Jefferson, Broadway, Columbia and 6th Avenue.

[h] The house was later enlarged with an extended wing and another floor added with mansard roofs in the Second Empire style with these later additions made by architect William P.

[24] She sold the Ladd house and the downtown block it occupied for an intended hotel, which was never built, as the Depression began.

[26] In the 1880s Ladd was suffering from a growing paralysis of his legs and had to steer a Bath chair pushed by an attendant for mobility, although once he was seated behind his desk visitors would not necessarily have known, and he continued his business and philanthropic activities with the aid of his eldest son, William M.

[31] The SS William S. Ladd Liberty ship (#2084) honouring his memory was launched on September 13, 1943, and was sunk by Kamikaze attack on December 10, 1944, 11 miles south of Dulag, Leyte, Pacific Islands.