Tippett is an Australian netball player and former basketball player. In 2012, Tippett made a switch from basketball in 2012 and is currently playing for the Queensland Firebirds. In 2014 she made her ANZ Championship debut after signing with the NSW Swifts for 2014/2015. After the 2014 season, she was released from her contract with the Swifts, signing with Queensland Firebirds. She was selected in the Australian Diamonds squad for the 2018/19 international season. She was part of the 2015 and 2016 Premiership winning teams. 

Gretel has twice been named in the Super Netball Team of the Year, in 2018 and 2019. In the latter year she was also awarded the Liz Ellis Diamond, the most prestigious annual award in Australian netball, given to the player judged the best in both domestic and international netball throughout the calendar year.