Florida Partners in Education and Research for Kindergarten Success (PERKS) was an effective, large-scale professional development initiative to move Florida's early childhood workforce toward increased education and improved practices. This 7-month professional development intervention succeeded in increasing teacher knowledge, enhancing quality of the classroom literacy environment, and notably improving language development of children in high-need communities. These changes were generally sustained as seen in positive ratings of the classroom literacy environment a year later and children's maintenance of learning across the summer months prior to kindergarten entry. In addition, Florida PERKS provided preliminary answers regarding intensity of technical assistance needed to create positive change. Technical assistance delivered onsite was best, with no notable advantage found for weekly over monthly visits. To fully sustain change, however, may require continued support of teachers beyond a single school year when working with teachers who lack college degrees.