In its original English form, this is an insanely famous quotation in Japan. It is attributed to William S. Clark, formerly the president of Massachusetts State Agricultural College, who founded one of Japan's first universities, Hokkaido University in Sapporo. On his way home from Japan, he addressed his students at a station outside Hiroshima, and spoke these words.

Exactly what he said afterwards isn't fully known:

Boys, be ambitious like this old man. (one of Clark's students, 1894)

Boys, be ambitious in Christ! (unattributed)

Boys, be ambitious! Be ambitious not for money or for selfish aggrandizement, not for that evanescent thing which men call fame. Be ambitious for the attainment of all that a man ought to be. (as quoted in the Kojien)

So even though the quote is well-known, nobody is quite sure what Clark meant by it.

This is also the official English title of a Japanese film called Kishiwada Shonen Gurentai ("The Kishiwada Youth Gangs"). It was a slapstick manzai-esque look at high school gangs in working-class Osaka, and eventually led to two sequels directed by Takashi Miike.