We investigated the experiences of Australian autism early intervention service providers, including the professional development they receive on the job and how they translate research evidence into their practice. Semi-structured interviews were conducted with 15 providers drawn from three locations. Participants described the crucial role of paraprofessionals in early intervention services, and indicated that, within multidisciplinary teams, allied health professionals, and teachers are the ones who select intervention practices and upskill paraprofessionals. Furthermore, participants reported using practices supported by research evidence, but also some emerging and unsupported practices. The use of unsupported practices is examined in light of the daily challenges faced by centers. Results may inform further professional development in early intervention services for children on the autism spectrum, to support the best possible outcomes for this population. The findings highlight the potential need for job-embedded hands-on professional development conducted in real time.