What does it actually take to make an acquisition successful after the deal closes?

For most founders it is far from a finish line. You are expected to integrate the business, attract talent, inject founder DNA into the new organization, and take on meaningful new responsibilities. The most important thing is to have a very explicit conversation with the acquirer about your role going forward before you sign. In our case, one of the last things I did before the term sheet was present to the Grammarly board for two hours and we had a direct conversation about how the acquisition could go wrong, including the risk of role mismatch. That conversation shaped my entire role definition at the new company.