Mr Leslie Williams was a blacksmith from Tonypandy, Rhondda, Wales. He was a professional boxer (bantamweight) and was travelling to the USA under contract for a series of boxing contests. He was travelling with a fellow Rhondda boxer, David Bowen, and was the better known of the two. His ring weight was 8 stones 10 pounds (122 pounds or 55.3 kg). He was regarded as a promising fighter.
Williams was married with one son. He and Bowen booked passage through the Cardiff office of Dean and Dawson, tourist and steamship agents, 67 St. Mary Street, Cardiff (ticket number 54636, £16 2s).
They boarded the Titanic at Southampton as third class passengers, both died in the sinking.
Williams' body was later recovered by the Mackay-Bennett (#14) and was buried at sea on 22 April 1912.