[2] He was born in Edinburgh, Scotland, to Robert Burt Ranken, a wealthy and successful lawyer, and his wife Mary.

[5] Ranken's first exhibition in 1904 at the Carfax Gallery, managed by John Fothergill and William Rothenstein, in London was well received by artists and art critics.

[7] While in the United States, Sargent introduced him to Isabella Stewart Gardner, and he received commissions to paint portraits of the wealthy, including the Whitneys, Vanderbilts and Havermeyers.

Ranken died suddenly in London in 1941 and was buried near Warbrook, at St Mary (the church is off the A327 road, about 2 miles from the A30).

Following his unexpected death from a cerebral haemorrhage,[12] his sister Janette gifted over 200 works to be distributed amongst UK public galleries and museums.