The role of teachers has evolved from merely being teacher-centered to one that is student centered and the skills required for a quality teacher are changing too. Assessing teacher's effectiveness will not be a straight forward attempt by solely examining students' achievements or students' perceptions of their teachers' attributes. A careful examination of the teaching concepts, one as a form of "labor and profession" (Firestone & Bader, 1991); or the other as a "craft and art" (Grimmett & MacKinnon, 1992) will indicate that it involves teacher's cognitive ability and interpersonal skills (soft skills) which enhance teacher's performance in the classroom. Furthermore, the National Framework for Professional Standards (MCEETYA, 2003) has outlined that teacher's professional value (quality and professional knowledge and skills) will impact the management of student's learning. Based on these concepts, this study investigated a teacher effectiveness model. The framework of this investigation measured the teacher's cognitive ability (skills of assessment and evaluation, IT skills, and co-curricular knowledge) and the teacher's personality or interpersonal skills (soft skills). The respondents were experienced teachers working in Malaysia. A set of questionnaires with 120 questions were constructed by the researchers and were administered among 2000 school teachers from different types of schools. However, only 1366 completed questionnaires were analyzed while 634 responses were removed due to incomplete data. Utilizing structural equation model (SEM), this study attempted to ascertain the validity of the structural model of which teacher's cognitive abilities and personalities predict teacher's performances. The results revealed a model fit with both cognitive abilities and personality predicting classroom management. Good personality alone, however, is insufficient in terms of enhancing the teachers' commitment and responsibilities towards their students unless it is complemented by the teachers' cognitive competency (cognitive abilities). (Contains 3 tables and 3 figures.)