"When the going gets tough, the tough get going" is a popular proverb.
Phrase
The phrase is a play on words involving idiomatic (Proverb) and distinct meanings of "go" and "tough." In context, "the going" means "the situation," "gets tough" means "becomes difficult," "the tough" means "people who are strong or enduring," and "get going" means "become fully engaged." Taken together, the meaning of the phrase is "When the situation becomes difficult, the strong will become engaged."
The phrase is an example of antimetabole.
Another interpretation could mean, "Those who act tough and proud will vacate a situation when it becomes difficult lest they be proven not as tough as they appear to be."
The origin of the phrase has been attributed both to Joseph P. Kennedy (1888–1969), father of U.S. President John F. Kennedy, and sometimes to Norwegian-born American football player and coach Knute Rockne (1888–1931).