[14] Clark was nominated by President Franklin D. Roosevelt on June 10, 1938, to a seat on the United States Court of Appeals for the Third Circuit vacated by Judge Joseph Whitaker Thompson.

[12][18][19][20] On March 24, 1943, Clark resigned his judgeship and became a full-time member of the United States Army, this time as part of World War II.

[22] A unanimous decision by the United States Court of Claims held that he was not entitled to resume his post he left to rejoin to Army.

[21] In January 1948, he was appointed a civilian member of the legal staff of Genenal Lucius D. Clay, who was commanding the occupation forces in Germany.

He stayed in this position until 1954,[14] after being informed in 1953 that he was not going to be reappointed Chief Justice due to the diminishing amount of work for the court to preside over.

[27] Eight hundred guests were invited to the celebration at the Blairsden Mansion in Peapack-Gladstone, New Jersey, not far from the Clark family's own estate, Peachcroft.

[8] Before their divorce in 1947, they had three children, a daughter and two sons: On October 4, 1947,[32] Clark married for the second time to Sonia Tomara (1897–1982),[33] a foreign correspondent for the New York Herald Tribune, in Paris.