The Reverend Mr. Clement describes himself as a 'faded and indeterminate' character but is possessed of depths ill understood even by himself. These submerged dimensions of his personality have led to him making a very inappropriate marriage to a much younger and entirely unsuitable woman, and percipitating the crisis in Murder at the Vicarage with an uncharacteristicly 'revivalist' sermon.
Griselda describes her husband as '- very unexpected. I never feel I entirely know you.'
In The Murder at the Vicarage, Reverend Clement catches Lawrence Redding and Anne Protheroe kissing in the shed which Lawrence uses as a studio. He later advises Mrs Protheroe not to do anything rash, as to leave her husband would be a very serious step. He also advises Lawrence to leave St Mary Mead, as if he stayed, he would only make the situation worse for Mrs Protheroe.
The next day, Reverend Clement has an appointment with Colonel Protheroe at the vicarage. He receives a telephone call telling him that Mr Abbott of Lower Farm is dying, and so informs Mary that he will be late for the appointment. However, on reaching Lower Farm, he found Mr Abbott well, and Mrs Abbott denied making the call. When he arrives back at the vicarage, he finds Colonel Protheroe in the study, dead.
Reverend Clement comes across Lawrence Redding in the woods, carrying a large stone. Lawrence says that he is giving the stone to Miss Marple, for her rock gardens. Reverend Clement also finds a crystal of picric acid in the woods. The stone and the picric acid are later revealed to be part of a set up used by the murderer to produce an explosion, to produce a sound which would be interpreted as a shot.
Towards the end of the novel, Reverend Clement preaches a sermon exhorting sinners to repentance. After this, he receives a telephone call from Mr Hawes, saying that he wants to confess.
In The Body in the Library, Reverend Clement receives a visit from Mrs Price-Ridley, who tells him that a woman's body was found in Colonel Bantry's library, and that she has come to ask his advice.advice.
She tells him that she met Colonel Bantry on the train going up to London, and he had buried himself behind a newspaper, as if he did not want to talk. At Paddington, he got into a taxi, and she heard him give the driver an address in St. John's Wood. She considered this behaviour suspicious.