Feeling that he was too young to go to college, Knowles spent a year at Phillips Academy in Andover, Massachusetts.

[2] He shared half of the Nobel Prize in Chemistry in 2001 with Ryōji Noyori for "their work on chirally catalysed hydrogenation reactions".

The other half of the prize was awarded to K. Barry Sharpless for the development of a range of catalytic asymmetric oxidations.

He was married to his wife, Nancy, for 66 years and had four children, Elizabeth, Peter, Sarah and Lesley.

He and his wife had previously stated that their farm would be donated to be converted into a city park after their deaths.