[1] He was a descendant of Stephen Hopkins of the Mayflower and Edmund Rice an early immigrant to the Massachusetts Bay Colony.

[2][3] He first studied under Jeremiah Pearson Hardy, then moved to Boston, Massachusetts, in 1872 with his younger brother and fellow painter Wilbur Henry "Bibber" Lansil (1855–1897).

[4] In 1888 the brothers sailed to Europe, where Lansil studied at the Académie Julian in Paris and became enchanted with Venice, a city he'd paint for the rest of his life.

[5][page needed] Walter Lansil was a member of the Boston Art Club and The Society of Sons of the Revolution.

[6] Although the New York Times called him in 1897 "the celebrated Venetian painter", he also painted marine scenes, battles, and portraits.