Howard L. Seideman was inducted into the Wimachtendienk on August 5, 1915. He was one of seven Scouts inducted during the fourth week of inductions at Treasure Island, the largest class of new Arrowmen the summer of 1915. Seideman was inducted into Wimachtendienk as a youth, as was the case with all Arrowmen selected that first summer other than the founders. He was 17 years old at the time. By 1917, Seideman was on the Treasurer Island camp staff and also served as a member of the First Degree (Ordeal) ceremony team at camp as confirmed by the diary of Edward Frazier Evans. Seideman is the first youth Arrowman confirmed to have served as a ceremonialist (Harry Yoder had served as Guide and Guard at the first ceremony in 1915, but was not a part of the ceremony.)

His service to the Order continued in 1919, when he was elected Sakima, Chief of Wimachtendienk. In 1919, in recognition of his service to the Wimachtendienk, Howard Seidemen was elected to the Third Degree (Vigil). He kept his vigil with Horace P. Kern and is considered to be the fourth person to receive the Third Degree.

Seideman’s election to the Third Degree is significant because he was the first Arrowman originally inducted as a youth to keep the vigil. Seideman had just turned 21 the year he became a Third Degree Arrowman.