A promising engineer who totally loses his temper

Problem

In a context of cultural changes creating high tension in my company, one of my employees, Collin, was sometimes cold, arrogant, dismissive and moody, but he was very good technically, and very concerned with his position in the company. We had to work on a critical project and I organized a team meeting to talk about it, but unfortunately didn't make it, due to another meeting running late. I sent some instructions to my team in order for them to start without me. Collin started to run the meeting in my absence, and because he has some experience and was good technically, he started to run down the issues aggressively, following my guidelines. Others had not read my message and started objecting and dwelling into details. Collin totally lost his temper and started to yell at one of his colleagues in front of everyone. I arrived at the end of the meeting, and the colleague in question came to see me and asked me to initiate a complaint process against Collin.

Actions taken

I met the HR who advised me to ask Collin to apologize to his colleague. We decided to create a weekly 1:1 with my HR to have a chance to keep up with HR issues on a more regular basis. Then, I had a conversation with Collin and told him that I had really appreciated him taking the initiative to run the meeting and giving guidance to his colleagues. However, I told him his irascible behavior was unacceptable, and that because of it he will be isolated on a project, and had lost a chance to become a leader. I also point blank told him the next time he would yell at somebody, he would be fired. I also tried to understand why he had behaved in this way, and it appeared that his stress came from some personal circumstances causing him a lot of stress. So, I offered him an opportunity to work from home a little bit more in order to make things easier for him. Finally, I met with everyone in the team and told them the content of that meeting with Collin, and had a long discussion with the person he aggressed to reassure him.

Outcome

I also understood that Collin's attitude also came from a feeling of misunderstanding or inferiority, so I gave him a long term roadmap for his project and made sure he understood the importance of his contribution to the company. Talking with Collin, and offering him the chance to work from home more often helped a lot, and he seemed happier. He and his colleague manage to work together now in a cordial way. His productivity blossomed and his colleagues recently mentioned he was a pleasure to work with again