Christopher St. John "Sinjin" Smith (born May 7, 1957) is an American former professional beach volleyball player.

He was the first player to win 100 career tournaments, and won numerous Manhattan Open titles with Karch Kiraly and Randy Stoklos as partners.

[4] In his senior year in 1979, the Bruins defeated cross-town rival USC to win the National Championship.

[5] Smith began to compete as a professional in the two-man beach volleyball tournaments of Southern California at age fifteen.

[10] The pair also appeared in the 1990 film Side Out as the nemesis team of Rollo Vincent (Stoklos) and Billy Cross (Smith).