In August 2009, he was voted as "Bundesliga Player of the Month". He then scored a hat-trick for Bayer Leverkusen against Stuttgart on 29 November 2009, sending the club to the top of league table with a 4–0 win, three points clear of closest challengers Werder Bremen. On 16 March 2010, Kießling signed a contract extension with Leverkusen, tying him to the BayArena side until 2015. He continued his impressive form in the 2009–10 season, scoring 21 goals in 33 games and finishing the season as the second highest goal scorer in the Bundesliga after Edin Džeko, with 22. He was also included in the "Bundesliga Team of the Season". Kießling finished the 2010–11 season with nine goal in 29 matches.