Rossi was husband of JW's model Carmen Rossi (see #04818) who JW set up as proprietor of the Académie Carmen.
Rossi appears to have been a piano tuner. However he was also described by Cyrus Cuneo as 'the excitable Italian attendant'. After the closure of the Académie Carmen, JW wrote to Carmen in March 1901 of his 'high esteem' for Rossi (#05352).
R.L. Brown, Lonely Americans, 1929, pp.76-80; Cuneo, Cyrus, 'Whistler's Academy of Painting,' The Century Magazine, vol. 73.