John Sheridan Weller was an attorney and politician.
He was the son of Frederick Simon Weller and Mary Ann Hammer and attended Bedford County Public Schools.
He graduated from Pennsylvania State College as a civil engineer in 1889 and began working for the United States. National Geodetic Survey.
The couple had no children. After reading for his law examinations, he was admitted to the bar of Bedford County in 1891. In autumn of 1901, he moved to Pittsburgh, where he became a partner in the law firm Weller, Wicks and Wallace.
In this capacity, he frequently represented Mike Benedum, who together with Joe Trees developed oil fields by gaining leases for exploration and drilling.
He specialized in the laws governing oil and gas properties.
From 1894 to 1897 he served as district attorney for Bedford County, and in 1898 was elected a member of the Pennsylvania State Senate from the 36th District.