His teachers included Eduard Fenzl (1808–1879) and Franz Unger (1800–1870) but he was also influenced by the physiologist Ernst Brücke (1819–1892).
In 1870 he became a professor at the forestry academy of Mariabrunn, and from 1873 to 1909, was a professor of plant anatomy and physiology at the University of Vienna, and at the same time (1866 to 1880) had a teaching position of technical commodity science at the Vienna University of Technology.
During his career, he took part in scientific expeditions to Egypt, India, Java, Sumatra, North America and the Arctic.
Recognised as an accomplished botanist and author of German language books and papers — his 1881 work on the movement in plants was read and discussed by Charles Darwin[6] — the genus Wiesneria commemorates his name.
Wiesner died in 1916 and was buried in the Grinzinger Cemetery and marble memorial was erected at the University of Vienna in December 1927.