[2] Next, Seawell entered private practice with W. F. Cowan in Santa Rosa and held a series of public posts.

[6][7] In October 1898, he was nominated by the Democratic Party in the First District and ran unsuccessfully for United States Congress.

[11][12][13][14] In June 1911, he lent his courtroom to the Santa Rosa Equal Suffrage Association to hold its meeting for the right of women to vote.

In November 1922, Seawell was elected as a member of the Supreme Court of California, defeating Charles A. Shurtleff, whose term ended December 18, 1922.

[18][19][20] In August 1939, Governor Culbert L. Olson appointed Jesse W. Carter to fill Seawell's seat.