The Handbook of Qualitative Research, co-edited with Yvonna Lincoln in 1994, has gone through four subsequent editions (2000, 2005, 2011, 2017) and is considered the primary reference volume in the field.

Denzin as a co-editor (1998a, 1998b, 1998c, 2001, 2002, 2003, 2006, 2007, 2008a, 2008b, 2008c, 2009a, 2010a, 2011, 2012, 2013, 2015, 2017a, and 2017b) or sole author (2009b 2010b, 2017c) has been continuously advancing the theoretical knowledge of qualitative research and developing strategies for application practices.

H. L. (Bud) Goodall, Jr., an American scholar of human communication, praised Denzin as a leading qualitative researcher and stated, In the 1970s, Denzin established himself as a scholar in symbolic interactionism with the publications of two works, The Research Act: A Theoretical Introduction to Sociological Methods (1970), and Childhood Socialization: Studies in Language, Interaction and Identity (1977).

Herbert Blumer (1900–1987), a leading American sociologist in symbolic interactionism, believed that The Research Act is "A first class work.

He recommends a new definition that recognizes children as individuals seeking meaning for their own actions, in which language plays a key role for them to develop a sense of self.

Denzin demonstrates how children enter into a process of sequential development that leads to self-awareness, socialized abilities and attributes such as pride, dignity, and poise.

Altheide believes that Denzin's cinema studies provide a new paradigm and a new methodology with an aim to understanding social life.

He writes from sound knowledge about alcoholism--which, unlike other diseases, is frequently viewed with bittersweet romanticism.”[9] Denzin's works in semiotics, structuralism and cinema studies led him to further incorporate postmodernism and post-structuralism in his repertoire as a cultural critic.

Denzin utilizes ideas embedded in postmodernism, poststructuralism, feminism, cultural studies and Marxism to address issues associated with the self and the society.

Denzin criticizes inaccurate conceptions of emotionally disturbed people without paying attentions to their inner lives and the ways they relate to others.

Denzin further incorporated justice studies and social activism in qualitative research, and published a co-edited volume, with Yvonna Lincoln, 9/11 in American Culture (2003).

In this volume, Denzin and Lincoln gathered a number of leading cultural studies and interpretive qualitative researches to address varied emotional and critical responses to September 11, a cataclysmic event, and provide suggestions on how to make sense of this tragic event, what the place of the humanities and the social sciences might hold in an age of terror, and so forth.