Eventually he entered Trinity College, Dublin, graduating with a B.A. in 1879. In that same year he was ordained, becoming curate at Tadcaster. In the late autumn of 1881 he became Vicar of Newland and, in February 1882, married Miss Rose Harrison of Cottingham. He received an M.A. in 1883, Bachelor of Laws in 1884 and Doctor of Laws in 1885.
In the 1880s, Malet Lambert was instrumental in the setting up of what later became the parish of St. Augustine's, Queens Road, a district taken out of his own parish of St. John's, Newland. In the 1890s the church of St. John, Newland was increased in size.
In 1894 Malet Lambert became Rural Dean of Hull. In 1900 he became Canon of York.
Joseph Malet Lambert died, in 1931, at the age of 78. The historian, Edward Gillett, an “old boy” of Malet Lambert High School, writing fifty years later, in "A History of Hull", states that in the 1880s, the Rev. J.M. Lambert gave a strong lead in social reform in Hull.
Malet Lambert played a prominent part in the history of Hull from 1881 until 1931. He was involved in great reforms in education and social affairs. "Two Thousand Years of Gild Life", was published in 1891, in which he talks about the development of the guild system in England, with particular reference to Hull from the 14th to 18th century.
Malet Lambert was a member of the Hull School Board, and was chairman when it was dissolved in 1904. It was this Board which set up the Craven Street School which eventually became Malet Lambert High School. He became chairman of the Hull Higher Education Committee in 1905, a position he held until his death in 1931. He was also chairman of the Council of Hull University College from 1927 until 1931.
Malet Lambert High School opened in September, 1932.