Pataki failed to gain traction during his own presidential bid, polling only in the low single digits and consistently missing the threshold for participation in primetime GOP primary debates.
See more of Pataki on the campaign trail:
George Pataki on the campaign trail
George Pataki backs Marco Rubio's 2016 bid
Republican presidential candidate former New York Gov. George Pataki speaks at the Iowa State Fair Sunday, Aug. 16, 2015, in Des Moines. (AP Photo/Charlie Riedel)
Republican presidential candidate and former New York Gov. George Pataki participates a pre-debate forum at the Quicken Loans Arena, Thursday, Aug. 6, 2015, in Cleveland. Seven of the candidates have not qualified for the primetime debate. (AP Photo/John Minchillo)
Republican presidential candidate, former New York Gov. George Pataki speaks to supporters at the 'Stop Iran' protest Wednesday, July 22, 2015, near Times Square in New York. (AP Photo/Frank Franklin II)
Republican presidential candidate, former New York Gov. George Pataki smiles during a tour of the Moonlight Meadery as he campaigns, Monday, July 6, 2015, in Londonderry, N.H. (AP Photo/Elise Amendola)
Republican presidential candidate, former New York Gov. George Pataki speaks during a campaign stop at the historic Robie's Country Store, Wednesday, June 24, 2015, in Hooksett, N.H. Pataki is seeking the Republican nomination for president as he campaigns in the nation's earliest presidential primary state. (AP Photo/Jim Cole)
Former New York Gov. George Pataki, right, stands next to Wisconsin Gov. Scott Walker as he shakes hands with former Maryland Gov. Bob Ehrlich during a fundraiser for the Belknap County Republican Committee aboard the motor vessel Mount Washington on Lake Winnipesaukee in New Hampshire, Friday, May 29, 2015. At left is former Virginia Gov. Jim Gilmore. (AP Photo/Charles Krupa)
Former New York Gov. George Pataki announces his plans to seek the Republican nomination for president, Thursday, May 28, 2015, at the historic town hall in Exeter, N.H. (AP Photo/Jim Cole)
Discover More Like This
BACK TO SLIDE
The New York Republican on Tuesday called Rubio "the best person to bring us together."
Former Arizona Sen. Jon Kyl also endorsed Rubio earlier this week.
Pataki's announcement comes one day after former Texas governor Rick Perry, another former 2016 hopeful, endorsed Ted Cruz as the next commander-in-chief. Perry will campaign with Cruz in Iowa this week.