The United States labour movement faces a potentially transformative moment, as workers have won breakthrough union organizing victories at various high‐profile, private‐sector employers. While winning an election is essential to establishing collective bargaining, unions then need to secure a first contract with employers to make tangible improvements in working conditions. Drawing on a sample of 126 responses about postcertification collective bargaining, we find that both employer and union tactics have significant impacts on first contract achievement. Employers continue to impede first contract achievement by committing unfair labour practices, but unions can improve their chances of establishing an agreement by utilizing tactics that engage the public.