Two men were walking along Wick Street on 13 January 2019, when they were approached by the defendant who offered them drugs.
When they refused, he pushed one man to the floor, causing him to sustain a dislocated ankle which required a steel plate to be fitted, and punched the other man in the face, causing a black eye, swelling and a chipped tooth.
The defendant then ran away from the scene after members of the public saw what had happened.
One of them recognised him and provided information to police, which led to him being identified as Linton Woolley, 33, unemployed, of Lavinia Way, East Preston.
He was subsequently arrested and charged with committing grievous bodily harm, and assault occasioning actual bodily harm.
He denied the offences but pleaded guilty just before the case was due to go for trial.
At Lewes Crown Court on 12 August, Woolley was sentenced to a total of 54 weeks’ imprisonment.