Her acting career started with her appearance in TV commercials and in a 2000 episode of Water Rats called "Jump in the Mouth". She landed her first lead role as Leah Pointin in the 2008 Australian film Newcastle.
Breeds played Cassie Cometti in series 3 of Blue Water High, but she made her first appearance in series 2, episode 3 as Tina. It was during filming on Blue Water High that she discovered she had been hired to play the role of Ruby Buckton on Home and Away, and her first scenes aired in June/July 2008.
About her Home and Away character, Rebecca says "Ruby has gone through a lot, mostly now having a disease and had to gain a level of independence I really admire. She is free-spirited and sure of who she is. I love playing Ruby; she is cheeky and easy-going, but very passionate about her family and friends."
Rebecca has taken music and drama classes since she was 6, and completed years 11 and 12 on a music scholarship. During this period, she performed with various ensembles and toured around America.