At the 1968 Australian Paraplegic Games in Perth, he won two gold medals in backstroke and breaststroke.
His breaststroke time of 64.1 seconds equalled his Australian  record.

At the 1968 Tel Aviv Paralympics, he won a silver medal in the Men's 50 m Breaststroke class 3 complete event and narrowly missed out on a bronze medal in backstroke and wheelchair sprint.
At the 1970 Commonwealth Paraplegic Games in Edinburgh, he won two bronze medals in breaststroke and backstroke.

In 1983, the Australian Wheelchair Tennis Association selected Simmonds together with nine other wheelchair athletes as linesmen for the 1983 Custom Credit Indoor Tennis Championships.
This followed the suggestion of John Newcombe, famous Australian tennis champion.
 Simmonds, secretary of New South Wales Wheelchair Tennis Association, assured the public that the linesmen would be able to handle John McEnroe and other competitors.
 Well-known Australian radio announcer John Laws informed the public that "Jeff is one of the tough, no nonsense linesmen Superbrat will encounter at this year's Custom Credit Indoor Championship."
According to Newcombe,  most linesmen selected were able bodied before their injury, “They have great reflexes and good eyesight and they are involved in the game already so they should make good linesmen”.
At the 1968 Australian Paraplegic Games in Perth, he won two gold medals in backstroke and breaststroke. His breaststroke time of 64.1 seconds equalled his Australian  record. 
At the 1968 Tel Aviv Paralympics, he won a silver medal in the Men's 50 m Breaststroke class 3 complete event and narrowly missed out on a bronze medal in backstroke and wheelchair sprint. At the 1970 Commonwealth Paraplegic Games in Edinburgh, he won two bronze medals in breaststroke and backstroke.
In 1983, the Australian Wheelchair Tennis Association selected Simmonds together with nine other wheelchair athletes as linesmen for the 1983 Custom Credit Indoor Tennis Championships. This followed the suggestion of John Newcombe, famous Australian tennis champion.  Simmonds, secretary of New South Wales Wheelchair Tennis Association, assured the public that the linesmen would be able to handle John McEnroe and other competitors.  Well-known Australian radio announcer John Laws informed the public that "Jeff is one of the tough, no nonsense linesmen Superbrat will encounter at this year's Custom Credit Indoor Championship." According to Newcombe,  most linesmen selected were able bodied before their injury, “They have great reflexes and good eyesight and they are involved in the game already so they should make good linesmen”.
Jeff Simmonds