In an interview with the BBC, the actress stated that she is still amazed to be playing the role nearly 40 years after first signing on as the third Doctor's companion in 1973.
"I'd have to go back to Barry Letts – my first producer on Doctor Who. I owe him not just a great debt for work but for the way he handled the programme and my character," she said. "I was also fortunate with my Doctors, Jon Pertwee and Tom Baker, because I think we worked so well together."
Sladen also remarked that she tries to maintain Sarah Jane's child-like sense of justice in her own life.
She further explained: "There are things I aspire to in Sarah Jane. She has a huge frailty but she won't give up. She almost has a child's sense of what's fair and what's not fair.
"It's something you have to lose as an adult but she just doesn't let go of that and maybe that is something that makes people feel safer. I don't know what her appeal is really but I love her – I really do."
The Sarah Jane Adventures is to return for a fourth season in October on CBBC.