Bristol Palin was paid €182,000 to front a poster campaign for an anti-teen pregnancy organisation – seven times more than the group spent on initiatives to lower pregnancy rates.
Miss Palin, the eldest daughter of the former Republican vice-presidential candidate Sarah Palin, was made a "teen ambassador" for The Candie's Foundation in 2009.
Newly released tax filings show the 20-year-old was paid $262,500 by the non-profit group for her work, which included posing for publicity material with her two-year-old son, Tripp.
Candie's – which has been criticised for running overly sexualised advertisements – gave $35,000 (€24,500) to two programs aimed at countering the rise in unwanted teenage pregnancies.
Defending the figures, the group said that Miss Palin's appearance had ensured its campaign had a "tremendous reach" among young women.
"Bristol Palin has been a courageous and powerful partner to the foundation as we attempt to discourage teen pregnancy," the group said in a statement posted to its website.
The documents also disclosed that the group's president, chief financial officer and chief lawyer were paid almost €9m a year between them.
Miss Palin had Tripp when she was 18. Her pregnancy was announced soon after her mother was named John McCain's running mate in August 2008. She has since separated from Tripp's father, Levi Johnston.