Internalization of leadership values by school principals is needed in increasing teacher professionalism. With professional teachers, teacher competence can be fulfilled, the learning process is quality, and the quality of schools can be increased. In this study, a qualitative descriptive approach was used, because the researcher wanted to conduct in-depth research by searching data on subjects or informants so that researchers could clearly describe the situation regarding the internalization of the principal's leadership values in increasing the professionalism of teacher work at Al Akbar Singosari Islamic Middle School. . The type of research used is a case study, which is a process of gathering information in depth. The research results obtained by researchers from interviews, observations, and documentation show that the planning carried out by the principal in increasing teacher professionalism at Al Akbar Singosari Islamic Middle School is carried out simultaneously with the annual program and the school semester program. the leadership values that are internalized by the principal are moral values, responsibility, and ukhuwah. The principal evaluates at every routine meeting for general issues and evaluates personally for issues involving someone's disgrace.

Karreza, I. (2021). Nilai-Nilai Kepemimpinan Dalam Buku Siswa Kelas Vi Sd/Mi Tema 7 Kurikulum 2013. Purwokerto : PGMI UIN Professor Haji Saifuddin Zuhri. Disertasi tidak diterbitkan.

Hanifa, Hayun. (2016). Internalisasi Nilai-Nilai Kepemimpinan Melalui Kegiatan Ekstra Kulikuler Hizbul Wathan di SMA Muhammadiah 1 Ponorogo. Skripsi. Program Studi PAI.

Ariyani, Rika. (2017). Kepemimpinan Kepala Sekolah Dalam Pengembangan Profesionalisme Guru. Jurnal Al-Afkar. Vol 5 (1) 117-119.

Meleong, Lexy.J. (2016). Metode Penelitian Kualitatif. Bandung: PT Remaja Rosdakarya.

Hamid, Abdul. (2016). Metode Internalisasi Nilai-Nilai Akhlak Dalam Pembelajaran Pendidikan Agama Islam Di SMP Negeri 17 Kota Palu. Jurnal Pendidikan Agama Islam, Vol. 14 (2) 167-198.

Kementerian Pendidikan Dan Kebudayaan. 2012. Pembinaan Dan Pengembangan Profesi Guru Buku 2. Badan Pengembangan Sumber Daya Manusia Pendidikan Dan Kebudayaan Dan Penjaminan Mutu Pendidikan Pusat Pengembangan Profesi Pendidik. jakarta. 35 hal.