He gained sufficient experience in legal matters in that employment that he passed the bar exam in 1889 and immediately began to practice law in Kansas City, successfully defending Jesse E. James, son of the bandit Jesse James, on an accusation of train robbery in that same year.

[6] Walsh told a reporter, "Our purpose is to inquire into the general conditions of labor in the principal industries of the United States, including agriculture, into relations between employers and employees, conditions of sanitation, safety, methods for avoiding or adjusting labor disputes through mediation and negotiation, the smuggling of Asiatics into the United States or its possessions, and the underlying causes of dissatisfaction in the industrial situation.

"[7] Walsh investigated labor-management clashes from 1913 to 1918, and in 1918 was named co-chairman, with ex-President William Howard Taft, of the National War Labor Board.

He was a co-Vice President of the Friends of Indian Freedom society and in 1919 wrote that "Were it not for my absorption, at present, in the Irish matter, I would throw myself into this Egyptian business with a will.

At the end of the case the WLB found in favor of the women's organization, and reversed a lower-court ruling on the subject.

Walsh told the board that the wage matter was one far above the law and went down into the deepest moral questions, the structure of society, and even into the fundamental religion .

[3][16] Walsh served as the first legal counsel to the Amalgamated Association of Iron and Steel Workers, remaining in that role from 1918 until his death in 1939.

They had nine children: Jerome, James, John Frederick, Frank P. Jr., Cecelia, Virginia, Frances, Sarah and Catherine.