In the summer of 2006, Nečas took over at Bohemian Football League side FK Bohemians Prague (Střížkov), replacing Luboš Urban. However his tenure lasted just five matches before he was dismissed, having lost only once during this period. In 2007, Nečas joined Čáslav as assistant to manager Luboš Zákostelský. In September 2007, Nečas joined Gambrinus liga side Liberec as assistant to manager Michal Zach. Although Zach left his position in October 2007, Nečas continued in his position under replacement manager Ladislav Škorpil until they were both sacked, along with other assistant coach Luboš Kozel in November 2009. Nečas went to Slovakia to manage FK Senica in February 2010 during the 2009–10 Slovak Superliga. At the beginning of the 2010–11 season he went back to the Czech Republic and joined another Bohemian Football League club, Arsenal Česká Lípa. Having steered the club to mid-table safety, with the club in 11th position with just two games remaining, it was announced that Nečas would leave Česká Lípa at the end of the season. In the summer of 2011, Nečas joined Sezimovo Ústí in the Czech 2. Liga as assistant manager to Luboš Zákostelský. Nečas returned to Česká Lípa as manager in October 2012, achieving a win in his first match in charge. In October 2013 he took charge of FK Dečić in the Montenegrin First League. He took over from Roman Veselý as the manager of FK Kolín in March 2014, and the club celebrated the league title and promotion to the Czech National Football League at the end of the 2013–14 season. The son of Radim Nečas, also called Radim, is also a professional footballer.