In the 2006–07 season, Michálek emerged as a speedy, multidimensional player and an offensive threat, scoring 26 goals and 66 points.

[1] With the Senators, Michálek scored his first career NHL hat-trick against the Tampa Bay Lightning on 15 October 2009; two shorthanded and one on the powerplay.

[2] Michálek suffered a concussion after colliding with teammate Erik Karlsson on 13 December 2011, causing him to miss five games.

[4] He was later selected in fan balloting as a starter in the 2012 NHL All-Star Game and finished the season with a career high 35 goals.

Whilst injured during the 2015–16 season, Michálek was dealt to the Toronto Maple Leafs on 9 February 2016, in a blockbuster nine-player trade focusing around Dion Phaneuf heading to Ottawa.