In a bruising battle between two powerful forward packs, it was the Sharks who enjoyed a slight edge as their direct running took them over the advantage line and allowed their backs the space to run in four tries and notch a vital bonus point.
Frenchman Michalak scored a try and kicked four conversions and two penalties to keep the Sharks on the front foot.
The Sharks laid down an early marker as they kept the ball from the kickoff for 12 phases and two minutes and 25 seconds, loosehead prop Tendai Mtawarira and hooker Bismarck du Plessis carrying the ball strongly to fracture the Cheetahs defence and provide outside centre JP Pietersen with the space to dot down.
Michalak converted to give the Sharks an early 7-0 lead, but their ill-discipline at the ruck and the strong running of Cheetahs forwards Philip van der Walt, Adriaan Strauss and George Earle led to two penalties for flyhalf Riaan Smit.
The Cheetahs backs also have plenty of flair with ball in hand and outside centre Robert Ebersohn’s marvellous break from the restart led to powerful hooker Strauss muscling his way over for a try in the 32nd minute.
But Michalak struck back almost immediately with his try after a booming kick by fullback Riaan Viljoen had been allowed to bounce inside their 22 by the Cheetahs defence. The 29-year-old leapt up to get a hand to the ball, re-gathered and scored just his second SuperRugby try.
Wing Paul Jordaan then obstructed the Cheetahs chase at the restart and conceded a penalty, which Smit kicked to level the scores at 14-14.
But the Sharks attacked again with renewed vigour and, with the half-time hooter having just gone, they ran a penalty, with eighthman Keegan Daniel and Jordaan impressing with their handling to give wing Lwazi Mvovo the chance to beat the cover defence with dancing feet and a strong hand-off.
Michalak converted and then stretched the Sharks’ lead to 24-14 with a penalty six minutes into the second half.
Replacement flyhalf Sias Ebersohn kicked a penalty for the Cheetahs in the 53rd minute, as the Sharks, with Du Plessis in the sin-bin after a second shoulder charge earned him a yellow card, had their hands in the ruck.
The Cheetahs went into the final quarter just 20-24 down after Mtawarira infringed in the scrum and Sias Ebersohn kicked his second penalty.
The Sharks dominated the closing stages, however, as Michalak increased the lead to 27-20 with a penalty and the bonus point try came in the 73rd minute after Pietersen had stolen the ball on the right wing, Mvovo jinked his way deep into the Cheetahs 22 and replacement centre Meyer Bosman dived over the tryline.
Michalak added the conversion as the Sharks kept themselves inside the top six and the playoff places in the southern hemisphere competition.
Sharks – Tries: JP Pietersen, Freddie Michalak, Lwazi Mvovo, Meyer Bosman. Conversions: Michalak (4). Penalties: Michalak (2).
Cheetahs – Try: Adriaan Strauss. Penalties: Riaan Smit (3), S. Ebersohn (2).