He made his professional regular season debut in the Texans' season-opener against the Kansas City Chiefs and recorded one solo tackle in their 27–20 loss. In Week 3, McKinney earned his first career start after head coach Bill O'Brien opted to start the rookie over Akeem Dent. He recorded four combined tackles in the Texans' 19–9 win against the Tampa Bay Buccaneers. On October 18, 2015, he made his third career start and recorded three combined tackles during a 31–20 victory at the Jacksonville Jaguars. He left the game in the third quarter after sustaining a concussion and missed the next two games (Weeks 7-8). In Week 14, McKinney made a season-high ten combined tackles during a 27–6 loss to the New England Patriots. The following week, he recorded seven combined tackles and made his first career sack on Andrew Luck in the Texans' 16–10 win at the Indianapolis Colts. He finished his rookie season with 63 combined tackles (37 solo) and one sack in 14 games and 11 starts.
