Mr. Peggotty, the elder brother of David's old nurse, is a fisherman living in the coastal city of Yarmouth. Mr. Peggotty is also a good man. Mr. Peggotty is such a good man that we find it almost difficult to buy his character; he seems a bit one-dimensional, and we don't get much of a back-story for him.
Like Miss Betsey, Mr. Peggotty adopts strays into his home: he has raised his niece, Emily, and nephew, Ham, as though they were his own children. And he has also been supporting the widow of his business partner, Mrs. Gummidge, even though she is a wet blanket of the first order.
Mr. Peggotty is absolutely unselfish in his devotion: when he hears that little Emily has been seduced away from her fiancé by Steerforth – a man whom he loved and trusted. Mr. Peggotty immediately makes plans to track down Emily and save her. He gives only passing thoughts to revenge before deciding to focus all of his energies on finding his adopted daughter and making her comfortable and happy.
Like many of the virtuous characters in this book (including Peggotty and Tommy Traddles), Mr. Peggotty is filled with the milk of human kindness. He is overflowing with affectionate feeling for his family, and it's this affection that makes him a good man. We can contrast his generosity of spirit with the unyielding inflexibility of Mrs. Steerforth.
When Mr. Peggotty goes to see Mrs. Steerforth to ask if there is any chance of Steerforth marrying Emily (even though Mr. Peggotty already knows the answer), Mrs. Steerforth coldly offers him financial compensation in exchange for Emily's disgrace. She refuses to acknowledge that Mr. Peggotty's pain could be as bad as (or worse than) her own. Mr. Peggotty keeps his voice calm, but his response is full of feeling:
I am looking at the likeness of the face [...] that has looked at me, in my home, at my fireside, in my boat – wheer not? – smiling and friendly, when it was so treacherous that I go half wild when I think of it. If the likeness of that face don't turn to burning fire at the thought of offering money to me for my child's blight and ruin, it's as bad. I doen't know, being a lady's, but what it's worse. (22.13)
In this speech, we can hear Mr. Peggotty's distress at the betrayal of a man who came to his home and seduced away his daughter right under his nose, under the guise of friendship. We can also see Mr. Peggotty's horror at Mrs. Steerforth's coldness: that she could feel no shame for her son's actions against his daughter shows a lack of feeling that seems almost criminal in the value system of David Copperfield.
What makes it worse is that Mrs. Steerforth, a lady, should be so cold as to offer cash in exchange for Emily's shame. You may have noticed that women are often associated with deep feeling in this novel (think Dora, Agnes, and Emily). Mrs. Steerforth's lack of feeling makes her seem unfeminine as well as inhuman to Mr. Peggotty.
Mr. Peggotty spares no effort tracking down Emily, traveling to Europe and walking through France and Italy on foot in search of her. But it is finally in London that he is reunited with his darling. The two of them plan to sail to Australia to start over again. Mr. Peggotty offers a place on the ship to Martha Endell and Mrs. Gummidge, neither of whom have anywhere else to go.
We last see Mr. Peggotty on a brief stay in England after some time in Australia. He has only returned to say his last goodbyes to David's family and to Peggotty, and to gather up a bit of earth from Ham Peggotty's grave as a memento for little Emily.