Watson was born in Mexborough, Yorkshire, the son of a headmaster in a mining community.

[1] For several years, he devoted much time to working as a guided fell-walking leader,[7] as well as to organic vegetable gardening, until very shortly before his death in 2005.

[6] Watson did not smoke, consume alcohol, or make contact with foods or substances which he regarded as toxins.

[9]: 4  (However, Watson remained a member of the London Vegetarian Society to keep in touch with the movement.

[1] He ran the publication single-handed for two years, writing and duplicating the newsletter, and responding to the increasing volume of correspondence.

[3] Watson expanded the vegan philosophy to object to any harm to living creatures.

A committed pacifist throughout his life, he registered as a conscientious objector in World War II.

[13][14] In November 2019, a blue plaque was unveiled in honour of Donald Watson at his former Doncaster Road School, in Mexborough, South Yorkshire.