The results of poll showed remarkable transformation in public attitudes, as the rise was seen from a low of 32 percent of registered voters just nine years ago in the Post/ABC poll.
According to the Christian Science Monitor, support for gay marriage, though, has gone from 47 percent to the current 58 percent in the last three years.
The poll result comes on the day when former Secretary of State Hillary Rodham Clinton announced her support for gay marriage, a signal that she may be preparing to run for president in 2016.
Last Friday, top Republican Senator Rob Portman of Ohio, a short-lister for the Republican ticket in 2012, also voiced support for gay marriage, revealing that his son is gay.
The poll found that younger Americans favored gay marriage much more widely than seniors. Nearly 81 percent of those below the age of 30 favor it, while only 44 percent of senior citizens do.
According to the report, the poll found that by a wide margin, 64 to 33 percent, Americans want the legality of gay marriage to be decided 'on the basis of the US Constitution', not state by state.
Currently, marriage laws are set by each state individually.
Gay marriage is legal in nine states and the District of Columbia. Another eight states provide for civil unions. In 31 states, gay marriage is prohibited by state constitutional amendment, the report added.