You can learn about Professor McAdams here.
You can also download his papers here.

Among his papers, the one that most clearly state his Theory of Personality is: A new Big Five: Fundamental Principles for an Integrative Science of Personality.

Prof. Dan P. McAdams

I love his theory because it offers a good framework for thinking about personality and about change.
I love it because it is science. I love it because it talks about “integration”. It sure helped me integrate my knowledge and my experience about personality and change. I can see people have traits. I find the Big Five Questionnaire very useful in my work. At the same time I see people change. Being a coach means being a change agent, and my coachee demonstrate their ability to change, in impressive ways, day in and day out.

I encourage you to read the paper.
However, here it is in a nutshell.
Personality is conceived as:

1. an individual’s unique variation on the general evolutionary design for human nature
   Mc Adams’ framework is based on evolutionary psychology. He makes it very clear that evolutionary psychology is not just another theory. In his words: “most of the grand theories are faith-based systems whose first principles are untested and untestable (Mendelsohn, 1993). In contrast, we contend that an integrative science of persons should be built around a first principle that enjoys the imprimatur of the biological sciences”.
2. expressed as a developing patterns of dispositional traits
   After the attacks launched on the concept of traits in the 70s, “not only did the concept of the trait survive the attacks, it emerged stronger than ever before”. Personality trait scores do predict observed behavioral trends across situations and over time. They do predict important life outcomes. Traits show long-term stability. They have strong heritability quotients (about 50%). Links between certain traits and the functioning of the brain are emerging. The Big 5 itself has proven to be a useful and coherent framework for organizing traits, maintaining its validity across cultures.
3. characteristic adaptations
   Plans, strategies, cognitive styles. Beliefs, values. Goals and motivational concerns. All these are characteristic adaptations. Characteristic because they are ways in which the character is expressed. Adaptations because they are unique to the individual, they are contextualized in time and space, they are triggered by specific roles and social demands.
   This is one level where change happens. This is the level where we operate as coaches, therapists and change agents.
4. and self-defining life narratives
   These are the stories individuals construct to make meaning and identity in the modern world.
   Each one of us has a life story. The more it matches our traits and our characteristic adaptations, the more it is healthy. This is another level where change happens. Coaching can be seen as a joint venture between the coach and the coachee to edit, reframe and construct empowering self-narratives.
5. complexly and differentially situated in culture and social context.
   Culture. It provides context for expressing traits and characteristic adaptations. Extraverts in Kyoto express their sociability differently from their equally extraverted middle class Americans in, say, Cleveland. Culture. It provides a menu for life narratives. No person is ever exposed to the same menu. Each person chooses from the menu.

Tags: Big Five, Change, coaching, McAdams, personality