His father, Nathan Ostrer, was a jewellery salesman who emigrated from the Russian Empire.
In addition to assembling a media empire he wrote poetry and authored an economics text.
[2] He began his career in the textile industry before establishing two banks with his brothers.
His son was Vivian Kaye (Kiki)Osborne, ne Ostrer.
A painting of Isidore Ostrer by Howard Coster is in the National Portrait Gallery.