Der Mann trägt ein kariertes Hemd. – Das karierte Hemd steht ihm sehr gut.

When the noun follows an indefinite article, the adjective (in the nominative and accusative cases) takes the ending of the definite article.

But if there is a definite article before the noun, the adjective takes the endings -e or -en.

Masculine:
der schicke Pullover (Nominative)
den schicken Pullover (Accusative)
Feminine:
die schicke Hose (Nominative und Accusative)
Neuter:
das schicke Hemd (Nominative und Accusative)
Plural:
die schicken Schuhe (Nominative und Accusative)

In the accusative, adjectives before masculine nouns have the ending -en.
Adjectives before nouns in the plural have the ending -en.
In the dative and genitive cases, the adjective ending after a definite article is always  -en.

Here is an overview of adjective declensions after a definite article: