On Thursday, he became the first Irishman to win at the event in 116 years.
The 27-year-old came second in the 4km individual pursuit at the championship.
Less than an hour later he claimed gold in the scratch race, and earned the title of World Champion in the 15km tactical bunch race.
Speaking from the Velodrome in Minsk Brian Nugent, Head Coach of Cycling Ireland, told Cycling Ireland: "It's hard to find the words. Absolutely astounding! That was the most exciting race I have ever seen.
"Martyn attacked 10 laps out and just held on and on. Even when the Austrian caught him and tried to pass on the last lap, Martyn just wouldn't give in and kicked one last time to win. A great day for Irish cycling."
Cycling Ireland CEO Geoff Liffey said: "This is an historic and tremendous day for Ireland, with our first World Track Title in modern times.
"This result confirms Martyn's ability, and confirms the progress being made by all the team working with him. It makes you wonder what more we could achieve if we had an indoor facility at home," he added.