 Whilst at Oxford he became a Freemason in the Apollo University Lodge, a Masonic lodge for students and former students of the university.He married Rosalind Watney in 1911, and had one son, Charles Anthony Lyell (later 2nd Baron Lyell) and one daughter.Lyell was elected to represent East Dorset in a 1904 by-election, and was appointed as Parliamentary Private Secretary to Sir Edward Grey, the Foreign Secretary, in 1906.