Frank Miller spent many days hungry and out on the street until he got a drawing job for Daredevil, later he became the writer. He originally was only going to write comics but then taught himself to draw well, with help from his art teacher. Initially he wanted to do crime comics but realized there were none so he adjusted to people who wore spandex.
He got a job on a second-tier character called Daredevil. Marvel probably figured that since the book was already going to be canceled that how bad could this guy really be. Miller took out cheesy villains like The Owl and Stilt-Man and replaced them with crime lords like Kingpin and assassins like Bullseye. He made his girlfriend Karen Page a drug addict and introduced a new love interest for Daredevil called Elektra, his college girlfriend who was now an assassin for hire. After 14 issues in Daredevil Miller killed Elektra and although fans were shocked they admired the artistic guts it took to kill such a popular character. Later Marvel brought her back.
Miller questioned the traditional non-lethal justice superhero when he revived a 1970's vigilante called: The Punisher. After the mafia guns down and kills his family Frank Castle launches a one man war on crime and actually kills people.
Frank then went on to write one of most adult comics of all time. It was a four issue mini-series of the future called Batman: The Dark Knight Returns. It pits an aging Batman against deadly foes and a corrupt society. For Miller's Batman the biggest problem isn't the Joker but Superman a well minding boyscout enthralled to Ronald Regan, fighting one mans secret wars in South America. Former Batman writers had actually called Miller and told him that he had ruined their character. In the mainstream media it got a lot of attention positive and negative but mostly positive. This along with Watchmen got rid of the general innocence of superhero's. Later Frank's dream would finally come true and he would get to do a crime comic called Sin City.