Walsh was a member of the New Jersey General Assembly in 1910 and 1911, and secretary of the Mercer County Board of Taxation in 1912 and 1913.

After leaving Congress, Walsh was engaged in the real estate brokerage business.

He served as an internal-revenue agent in New Jersey and Wisconsin from 1915 to 1920, when he resigned to engage in private practice as a consultant and adviser in the field of federal laws.

He was again appointed as an internal-revenue agent and served from 1933 until 1940, when he retired due to physical disability and resided in Palm Beach, Florida.

He died in New York City on August 5, 1953, and was interred in Our Lady of Lourdes Cemetery in Trenton.