He received his early education in Bolton and later attended Rochdale Academy..[7] After the death of his father, William Lassell was apprenticed to a merchant in Liverpool from 1814 to 1821.

He later made his fortune as a beer brewer, which afforded him the means to pursue his passion for astronomy.

In 1855, he built a 48-inch (1,200 mm) telescope, which he installed in Malta because of the observing conditions that were better than in often-overcast England.

On his return to the UK after several years in Malta, he moved to Maidenhead and operated his 24-inch (610 mm) telescope in an observatory there.

At the University of Liverpool the William Lassell prize is awarded to the student with the highest grades graduating the B.Sc.