Born on 15 November 1839 at Trowbridge, the son of a woollen yarn spinner of strict Nonconformist practice. He became a student teacher and, after studying at Borough Road Training College, taught at Lewisham and Portland. A natural student and omnivorous reader, particularly in English literature, his interests also included music and chemistry.
While he was teaching at the British School at Portland, a colleague, Mr. Beale, was forced to leave because he had been preaching for the Rev. William Hopper, the local BC minister, who had fallen ill. Hopper showed Beale an advertisement in the Bible Christian Magazine for the headship of the small BC grammar school at Shebbear. Beale was ineligible as he was married, but Ruddle applied and, in 1864, at the age of 23, he became the headmaster at Shebbear and held the post for 45 years. He resigned for reasons of ill health shortly before his death in 1909. Under him the school developed into an outstanding example of its kind and he heard himself described as 'the Thomas Arnold of North Devon'. In 1872 he gained an external BA from London University.
After accepting the headship Ruddle became a Bible Christian and a local preacher in the Shebbear Circuit, finding his wife, Margaret Allin, in one of the villages. She died in 1892. An original and forceful preacher, he preached the Conference sermon at Bristol in 1894. Active in the affairs of the Connexion, he served on the Committee of the Missionary Society, the General Connexional Committee, the Connexional Examining Committee and several others. He was part of the BC delegation to three of the Ecumenical Methodist Conferences, in 1881, 1891 and 1901, presenting a paper at Washington DC in 1891 on 'The Attitude of the Church towards Amusements' (more significant for its being given at all than for what it said!). At the first meeting of the UM Conference in 1907 he was elected one of the lay Guardian Representatives from the Bible Christians, an office he occupied until his death at Shebbear on 17 October 1909.