His self-portrait from 1745 and a portrait of his sister Anna Lisa (married name Askblom) show clear influences from Scheffel.
In 1745 Krafft went to Copenhagen, where he came under Carl Gustaf Pilo's influence, as seen in the 1748 autographed portraits of Anna Bohr and a Miss Leijonhufvud as a shepherdess.
In 1749, Per Krafft went to Skåne and painted Governor Wilhelm Lindenstedt's portrait in baroque style.
Krafft had a patron in Denmark's then Finance Minister Otto Thott, for whom he copied several hundred family portraits at various Danish castles, which were collected in Gavnø.
In 1752 Krafft painted the Count and Countess Thotts and their daughter's portrait, later kept in Gavnø and Frederiksborg Castle.
He later became a student of Alexander Roslin, a professor at Bayreuth and court painter to Stanisław August Poniatowski of Poland.
Krafft painted in Paris included Count Nils Nilsson Bonde and some genre portraits, for example a Young Girl who Plays Lira (1758).