"Hard" was sent to radio by Def Jam Recordings on November 10, 2009, as the second United States single from Rated R. It is a hip hop song and features military horns, hissing synthesizers, sharp beats and piano chords.

In an interview with MTV News, producer Mikkel S. Eriksen of Stargate initially confirmed "Wait Your Turn" as the second single from Rated R; however, "Hard" was ultimately chosen instead.

[3] In an interview with MTV, Rihanna explained that while she was in Paris, Christopher "Tricky" Stewart and The-Dream played a few songs for her, which included "Hard".

[9] As noted by Ailbhe Malone of NME, Rihanna adopts Jay-Z's vocal style in the lyric, "Brilliant, resilient, fan mail from 27 million.

"[13] Monica Herrerra of Billboard magazine wrote: "Rihanna effectively assumes the hip-hop posture and even recruits the ultimate street cred booster in rapper Young Jeezy, who provides the thrust needed to send a song with a somewhat inert chorus home".

[7] Alexis Petridis of The Guardian called "Hard" and "Rude Boy" the highlights of Rated R, and wrote, "both of which exploit Rihanna's most appealing vocal style, a sulky, icy, monotone".

Greenblatt wrote, "Rihanna dons hip-hop swagger like borrowed armor, leaning heavily on her Caribbean accent and unleashing a string of baddest-bitch boasts via dancehall-riddim'd bangers like 'Hard,' 'G4L,' and 'Wait Your Turn'".

[15] Ryan Dombell of Pitchfork Media wrote, "the bulletproof guise is good for the record's high point on 'Hard', a strutting statement of power bolstered by a roiling undertow of a beat from 'Umbrella' producer Tricky Stewart.

As the first chorus begins, earlier scenes from the video are intercut with each other; Rihanna is shown commanding her troops, firing a machine gun, and dancing in the bunker.

As the second verse begins, Rihanna is seen with slicked-back hair wearing a metal bikini top, rolling in mud and surrounded by troops on a stone structure before a mountainous backdrop.

As the second chorus starts, Rihanna, wearing a bullet bra and a helmet similar in appearance to the ears of Mickey Mouse, stands on a pink army tank.

Peter Gaston of Spin wrote that the video for "Hard" resembles "Janet Jackson's 'Rhythm Nation' meets Christina Aguilera's 'Dirrty' phase—Rihanna vamps in dimly lit outposts, dodges explosions in the desert, and, quite enticingly, takes a break from boot camp to smother herself with mud.

"[30] James Dinh of MTV News showed the video, on a small player, to fans in Times Square in New York City to ask their opinions.

[31] Bill Lamb of About.com wrote, "I must confess that I do fail to understand the point of Rihanna humping the gun turret of a pink tank dressed in Mickey Mouse ears.

[33] To promote Rated R in the UK, Rihanna performed the song with Jeezy at the launch of the Nokia X6 smartphone at Brixton Academy in London.

[34] Other songs on the set list were "Russian Roulette" and "Wait Your Turn" from Rated R, and "Don't Stop the Music", "Take a Bow", "Disturbia", and "Umbrella" (with Jay-Z).

[34] Rihanna performed "Hard" live at the 2009 American Music Awards on November 22, 2009, at the Nokia Theatre in Los Angeles, California, as part of a medley with "Wait Your Turn".

[39] To promote the single's release in the US, Rihanna appeared on The Ellen DeGeneres Show on February 1, 2010, where she sang "Hard" and "Don't Stop the Music".

[42] On March 27, 2010, Rihanna performed the song as part of a medley with "Rude Boy" and "Don't Stop the Music" at the 2010 Nickelodeon Kids' Choice Awards at UCLA's Pauley Pavilion in Westwood, California.