[1][2] William started his career as an apprentice at the age of 12 in 1827, aboard the Abram.
He completed his apprenticeship in 1835 and worked as a seaman in merchant ships and whalers until 1842.
On 15 February 1852, he was admitted as a younger brother of the guild of masters and pilots of Trinity House.
[3][4] In December 1867, after 26 years as a whaling master, William became harbour master at Hull and advisor to explorer Benjamin Leigh Smith.
Wells' first command was for the merchant ship Ann in 1842; he went on to captain many whaling ships: Helen (1844–45), St George (1846–49), Ann (1850–1853), Truelove (1854–1860 and 1866–1867), Emma (1861–62), Diana (1863), and Narwhal (1864).