He was staying at the Imperial Hotel in Tokyo but did not have any change available to tip the courier.
Instead, the Nobel Prize winner handed the man two handwritten notes, telling him: "Maybe if you're lucky those notes will become much more valuable than just a regular tip."
Einstein wrote on one of the notes: "A quiet and modest life brings more joy than a pursuit of success bound with constant unrest."
"Where there's a will, there's a way," he wrote on another sheet.
The notes, which were previously unknown to researchers, were auctioned off by an anonymous Hamburg resident and sold for NZ$1.89m in Jerusalem.
Roni Grosz, an Einstein archivist at Jerusalem's Hebrew University, said: "What we're doing here is painting the portrait of Einstein - the man, the scientist, his effect on the world - through his writings.
"This is a stone in the mosaic."