Promoting the wrong person to a management position

Problem

An engineer in my team wanted to advance in his career and at the time, the only way for him to advance would be to become a team lead. At the time, I thought anyone should have the opportunity to do whatever they wanted so I gave him a chance. However, I warned him about the fact that he'd be coding less, as he would have to deal with people problems. I helped him get promoted, but a few months in, some of his direct reports started complaining. One of them was even considering leaving. The fact was that he had kept writing code at the same level and was not able to deal with his new managerial responsibilities, as people skills were not something he was strong in. I had to take action.

Actions taken

I had a word with him about the situation and he agreed with my conclusions: he was not made for that role. I did not want to demote him so we agreed on him taking a pure engineering path. As a former architect, I coached him on that path and I decided to take on some of his team lead responsibilities, to allow him more time to prove he was able to work at that level. He is now a successful architect at the company.

Lessons learned

I am now a lot more careful when promoting people to leadership positions, and make sure they understand the people side of management. I try to spend more time teaching the responsibilities and also trust my gut feeling. I've also tried to use internal resources to help managers validate their choice: 1:1s with other managers but also 1:1s with HR. In my experience, they have been very good at acquainting people with their future responsibilities and at helping them to understand what it's like to be a manager. Finally, if, despite all the coaching work done before the promotion, my conclusion is that the person is not right for the job, and if there is no other path for them, I believe it's better to let that person go. It's better for them (they can find a company where they will be able to fulfill their career growth) and better for the company (you don't want to keep someone without being able to offer them career growth opportunities).