Alfred John Herbert Bottoms was born in Kensington, London in June 1918. Immediately  after the war, he began speedway competition, racing for Rye House in 1945. For 1946 he signed for Wembley and was a member of the Wembley Lions championship winning team. He did not race much in 1947 and joined the Southampton team as captain for the 1948 season helping them to win promotion. In 1949 he returned to Wembley and quit at the end of 1949.

1950 saw Alf enter the Formula Three circuit racing with his JBS-Norton in a team run by his father and brother, Charlie. J.B.S. standing for James Bottoms and sons. The J.B.S. was developed from the Cowlan Special of Coward and Lang. It was highly competitive and looked set to present a consistent challenge to the Coopers. Alf gave notice at the Goodwood Easter meeting, finishing third against experienced opposition.

In July 1950 Alf won the Première Coupe des Racers 500 at raced at Rheims in hot conditions, "Curly" Dryden took the lead but was soon passed by Alf. By the fourth lap Alf had begun to open a gap on the main pack of cars, though he was still closely followed by Åke Jönsson's Effyh. On the fifth lap Bottoms had 2.3 seconds over Jönsson. Dryden, the next driver, however was already half a minute behind the leader. The Coopers of Stirling Moss, Harry Schell and Raymond Sommer all struggled in the high temperatures. By lap seven his lead was up to seven seconds and two laps later it was 21 seconds! Pressing on at an amazing speed he won the thirteen-lap event by more than forty-seven seconds over Jönsson. Only three of the twenty four starters finished on the same lap. Moss, in a lightweight Cooper JAP, was one of the ones to finish a lap down in sixth place. It was Alf's finest race.

He also took a wins at Blandford in May from Peter Collins and Alan Brown, a Brands in the non production car race in June and a third place at Silverstone in August. In September, Alf won the Open Challenge race at Brands Hatch as well as the non production race.

In Alf's hands the JBS was becoming a credible rival to even the fastest Coopers, Alf winning the Earl of March Trophy in March 1951, beating Curly Dryden, also in a JBS. On 3rd May 1951 at the Grand Prix de Luxembourg, held on the Finden street circuit located beside Luxemburg airport, Alf's throttle stuck open during practice, he crashed and was killed instantly.