Pendleton was active in politics as a Democrat.[1] In 1886, he was an unsuccessful candidate for the West Virginia.[1]
In March 1889, he presented credentials as a Member-elect to the 51st United States Congress Congress and took his seat.[1] He served from March 4, 1889, to February 26, 1890, when he was succeeded by George W. Atkinson, who successfully contested the election.[1] Atkinson served out the remainder of the term, until March 3, 1891.[1]
In 1890, Pendleton was elected to the 52nd Congress.[1] He was reelected to the 53rd Congress in 1892, and he served from March 4, 1891, to March 3, 1895.[1] In the 53rd Congress, Pendleton was chairman of the Committee on Private Land Claims.[2]
Later life
Pendleton was an unsuccessful candidate for re-nomination in 1894.[2] After leaving Congress he resumed the practice of law in Wheeling.[2] He died in Wheeling on December 24, 1916, and was interred at Greenwood Cemetery in Wheeling.[2]