Fox News presenter John Gibson began his live radio show with a funeral anthem and described the actor as a "weirdo" with a "serious drug problem".
He played a clip from Ledger's film Brokeback Mountain, ending with the line "I wish I knew how to quit you". He then said: "Well, he found out how to quit you."
Gibson followed with a second clip in which Ledger's character says "We’re dead", before repeating the line himself and re-playing the quote.
He added that he was wondering if Ledger killed himself "because of the stock market or because of John Edward's poor primary showing".
Ledger was found dead at his Manhattan apartment on Tuesday at the age of 28.
The cause of death will not be determined for at least another week after an initial autopsy proved inconclusive.
> Obituary: Heath Ledger