Smith Family Genealogy Forum
You stated that he was the eldest son of his parents. I believe he was the only son. He had a sister, Ella Smith. I don't know if she was younger or older than he. Here is what I have on descendants of William Alden Smith, Senator from Michigan [very sketchy]:
Sen. Smith had one child, a son, William Alden Smith, Jr., b. 21 Apr 1893, who married on 11 Nov 1913, Marie McRae [daughter of Milton A. McRae of Scripps-McRae newspapers]. During WWI, he was serving Stateside as Commander of Kelly Field in TX, when he caught pneumonia and died [no exact date]. He had two children [do not know names or sexes]. His wife then married an Englishman [name unknown]and moved with her two children to London.
Senator William Alden Smith died 11 Oct 1932, Grand Rapids, Kent Co., MI, and is buried in Woodlawn Cemetery in that city.