Jennings was a slight Derbyshire half-back who played for Notts County before the First World War, making twenty appearances in 1913/14 when they won promotion from the Second Division with the towering Albert Iremonger keeping goal.

When Leeds City visited Notts County for a Midland Section game on 21 April 1916, they arrived a man short, and Jennings filled the gap, playing at outside-left in place of Willie Wilson, who was unavailable because of military duties. Five months earlier he had played right-half for County when they won 4-0 at Elland Road. The game at Meadow Lane produced a keenly fought 1-1 draw with the Leeds Mercury reporting: 'The Leeds forwards provided the spectators with some very clever passing, particularly Jennings, who, although playing in a new position, fully justified himself.'

After the end of the war, Jennings left Notts County to sign for Norwich City, and then moved on to Merthyr Town in 1920. A couple of years later he joined Northampton Town before a spell in non-League football with Peterborough & Fletton United before leaving for Canada to end his career with Hearts of Winnipeg.

He died in 1953.