In Part 1, Franklin talks about his reasons for writing the Autobiography, saying that since you can't live your life over again, the next best thing is to recapture it by writing it down. He describes his early life in Boston, his love for reading, and his job training. Franklin apprentices as a printer to his brother James, but he hates working for him, and runs away to Philadelphia at age sixteen.
In Philadelphia, Franklin begins working for a printer named Keimer. The governor, Sir William Keith, offers to set Franklin up on his own as a printer and sends him to England to get supplies. Once in England, though, Franklin finds out that Keith's a liar and a cheat – and he's stuck in London without money or a way to get back to America. Franklin works hard at Watts' printing shop, learns about his craft, and makes some important connections. After he saves up enough money, he returns to America with his friend Mr. Denham, who's offered him a job.
Franklin works hard for Denham until his employer dies, and then he has to go back to Keimer. That doesn't last long, because Franklin quits. He decides to start his own business with another former Keimer employee, Hugh Meredith. Even though there's competition, they get a couple of lucky breaks, like printing the Pennsylvania Gazette. After Meredith bows out, Franklin gets some contracts to print paper money, and his rival Keimer retires. As the business really starts to take off, Franklin marries his old flame Deborah Read. He also helps found a gentleman's club called the Junto, which is for talking about and debating philosophical and scientific ideas. One of their first big projects is creating a subscription library. Franklin stops writing here because of the American Revolution.
Part 2 begins with Franklin writing from Passy, France, receiving letters from two of his friends, Abel James and Benjamin Vaughan. They basically tell Franklin that he is awesome, that his life story is awesome, and he should keep writing it. Franklin's persuaded. Let's face it: we probably would be too.
He goes back to where he stopped in Part 1 and tells us more about how the Junto created the Library system, then about his personal work on achieving the virtues of modesty and thrift. Franklin writes a list of virtues and works on them daily. He says he doesn't go to church, but prays by himself: he leaves religion out of his virtue list and says he'll get to it later in a book called The Art of Virtue, which he never writes. He ends this section by saying pride is the hardest virtue to overcome, and he's still working on it.
Part 3 picks up five years later, with Franklin in Philadelphia. He writes Poor Richard's Almanac; it and his newspaper, the Pennsylvania Gazette, are really successful. His business continues to expand. Franklin develops his ideas about religion in two encounters with preachers, both of whom he likes. The first, Samuel Hemphill, advocates virtue, but he's cast out by the public because he copies other guys' sermons in his own (yeah, that's plagiarism). The second, George Whitefield, is a great traveling preacher who, Franklin says, has amazing rhetoric. Franklin's club, the Junto, gets bigger and founds the first American fire department.
On a personal level, Franklin reconciles with his brother James, who's dying, and explains how his own son Francis died of smallpox. Professionally, Franklin is made General Assembly Clerk and Postmaster. He decides Pennsylvania needs two things: a better military and a better institution for higher education. Franklin writes Plain Truth, which calls for a better military, but turns down a position as colonel; however, he's still got a lot of influence over Pennsylvania's militia. He also talks about the problems Quakers face as pacifists trying to contribute to a system of defense. With the Junto, he founds the University of Pennsylvania. Franklin also works on creating the first American public hospital, better paving for Philadelphia's streets, and a better system for dusting London's streets.
The French and Indian War is coming. Franklin writes a plan for uniting all the American colonies, but it doesn't go over well. They stay organized by individual colony. He helps General Edward Braddock get military supplies on credit from Pennsylvania citizens; since they don't know Braddock, Franklin has to put up collateral. This will bite him in the butt, though. In the middle of doing important military stuff – preparing for a battle at Monongahela to take over Fort Duquesne – Braddock doesn't listen to Franklin's advice. They lose the battle and Braddock is killed. Luckily, he gives Franklin a large chunk of the money before that happens. Another general, Shirley, comes through for Franklin with more of the money. (Franklin never gets the rest.) Meanwhile, Franklin helps build forts in Pennsylvania for defense against the Native Americans and learns about the Moravian religion. He's briefly honored as a colonel, but turns down a position as general.
Franklin also has scientific success: he works on experiments in electricity with his friends Peter Collinson and Ebenezer Kinnersley. Collinson tells the Royal Society about Franklin's ideas, and his work is published. He gets into a scholarly fight with Abbé Nollet, who has competing ideas, but the scientific public promotes Franklin's as the best. He's made a member of the Royal Society.
The new governor, Denny, is having problems with the Pennsylvania Assembly. The Assembly wants to pass a law that taxes colonists and Proprietors (the guys who own the colonies) more fairly to gather money for defending the colonies, part of which will be under the direction of General Loudon, but Denny won't sign it. Despite being delayed by Loudon, Franklin finally gets to go to London on behalf of the Assembly to work on mediation. (He never gets the rest of the money he covered for Braddock.)
In Part 4, Franklin consults with his friend Dr. Fothergill about the problem the Assembly's having and meets with Lord Granville, head of the King's privy council, about it. Lord Granville says the King makes laws just by talking, but Franklin argues that he can only approve/deny the colonists' laws once – he shouldn't be able to go back on his word. Lord Granville disagrees.
Franklin and the Proprietors meet at Thomas Penn's house to talk about the dispute, and Franklin has to argue with the other side's attorney, Ferdinand Paris. He and the colonists spend one year waiting for the decision. Meanwhile, the Assembly and Governor Denny finally agree on the bill. The Proprietors petition to keep the bill from happening, because they don't want to be tasked, and everyone goes to court. There, Lord Mansfield mediates the case, and everyone comes to an agreement.
The autobiography ends with the Assembly celebrating Franklin and firing Governor Denny. The colonists try to sue him, but don't succeed – he's too well connected.