I have a question about a potential letter of recommendation and whether it would be beneficial to my application. I worked at a government agency in D.C. every summer and winter break throughout college and some of high school even. A while ago, my boss introduced me to a very high up individual there and I have stayed in contact with him and he has been like a mentor to me ever since. He is a Presidential Appointee. He has a degree in Econ from Harvard and a Ph.D in Econ from Stanford. He was also a graduate professor at USC. My major is Economics which is why I was initially introduced to him.
My question is would this be a good recommendation even though I haven't directly worked for him in the past? Also, how many recommendation letters are too many? I was thinking about getting three.