“That my complicated life could be made so simple was astounding.”

Source: Blue-Eyed Devil

As quoted in Reader's Digest (July 1972)

Attributed on the internet but not found in print prior to an attribution in Aero Digest, Vols. 58–59, 1949, p. 115 https://books.google.com/books?id=q2ofAQAAMAAJ&dq=%22Life+is+simple%22+but+we+insist+on+making+it+complicated&focus=searchwithinvolume&q=%22Life+is+simple%22+
Misattributed, Not Chinese

Source: A Lodge in the Wilderness (1906), Ch. I, p. 22

Statement in Mainliner (July 1977), as quoted in Creativity and the writing process (1982) by Olivia Bertagnolli, p. 182; also partly quoted in Survival Skills for Managers (1981) by Marlene Wilson, p. 19
Variant: Anyone can make the simple complicated. Creativity is making the complicated simple.
As quoted in The Evaluation and Treatment of Mild Traumatic Brain Injury (1999) by Nils R. Varney and Richard J. Roberts, p. 303
Context: My son's a painter. All through school his teachers tell him he's a genius. I tell him to paint me an apple that looks like and apple before he paints me one that doesn't. Go where you can go, but start from someplace recognizable. Making the simple complicated is commonplace; making the complicated simple, awesomely simple, that's creativity.

“An Unprejudiced Mind,” p. 317
Pretexts: Reflections on Literature and Morality (1964)

Gewönlich wird eine Entdeckung nicht auf den einfachsten, sondern auf einem komplizierten Wege gemacht; die einfachen Fälle zeigen sich erst später.
Vom Radiothor zur Uranspaltung. Eine wissenschaftliche Selbstbiographie (1962).