How many letters does the top answer for “director of the cosby show” have?

The most common answer is alexander (9 letters).

Crossword clue: director of the cosby show

2 answers found in Letterora's clue database (Wikidata facts, Open Trivia DB, WordNet and Webster definitions — all licensed sources).

alexander 9 letters wd-fact-v3

king of Macedon; conqueror of Greece and Egypt and Persia; founder of Alexandria (356-323 BC)

pulliam 7 letters wd-fact-v3

director of that '70s show 67% similar → prepon

director of quiz show 50% similar → turturro