Jackie Fennell was Featherstone born and bred. In 1952, after showing outstanding schoolboy ability within the Featherstone area, Jackie was offered trials at the Rovers. He signed on in December of that year and immediately went into the first team at home versus York. Rovers won this game 15-12. In the very next fixture-against York away-he kicked his first goal for the Rovers. He was a prolific points scorer with 30 tries and 455 goals (number 6 on the all-time list behind other Rovers legends such as Steve Quinn, Cyril Kellett and Don Fox) from 321 appearances (12th on the Rovers all-time list with that Rovers legend, Jim Denton at number 1 with 440). This gave him a very large points total for his career of 1000 (number 8 on the all-time Rovers list behind such notables as Steve Quinn, Jim Denton and Terry Clawson).

Jackie played many of his games at fullback but he always considered his greatest match was at stand-off against Leigh in a 3^rd round Challenge Cup match in 1954-55 season in front of 19500 spectators. His life- long friend Joe Mullaney had broken a thumb, and Jackie as a last minute stand-in, equalised a Ledgard penalty just before half time to make the scores 2-2. After the break Jackie kicked 3 more goals and with a Don Metcalfe try and a Don Fox goal Rovers won 13-9. However, they were beaten in the semi-final 13-2 by Workington in front of 36 077 spectators.

1955-56 was also a very successful season for Jackie. He set up a goal scoring record of 102 which smashed the Freddie Miller record of 101 and at this stage he was only the second Rovers player to have topped the 100 mark. It is not surprising that he was the Rovers player of the year. Another marvellous season for Jackie was the 1957-58 where he also topped the 100 mark kicking 101 goals.

During Jackie Fennell's benefit year in 1962, George Potts, the then Sports editor of the Pontefract and Castleford Express, wrote of Jackie that, 'he was the best fullback never to have played for Yorkshire.