Ron Barber was sworn in Tuesday as the newest member of Congress, succeeding Rep. Gabrielle Giffords (D-Ariz.), who resigned in January to focus on her continuing recovery from injuries sustained in a shooting incident last year.

House Speaker John A. Boehner (R-Ohio) administered the oath of office to Barber on the House floor Tuesday afternoon. Seven other members of the Arizona House delegation and three of Barber’s grandchildren were at the new lawmaker’s side.

The event capped a tumultuous 18 months for Barber, Giffords’s former district director, who was injured along with the lawmaker and 12 other people in a January 2011 shooting outside a Tucson grocery store as Giffords met with constituents. Six people, including a 9-year-old girl, were killed in the shooting.

Ron Barber, left, gets a hug from former Rep. Gabrielle Giffords (D-Ariz.), last Tuesday in Tucson after Barber won a special election to succeed her. (Ross D. Franklin/AP)

Barber sustained serious injuries from the shooting and spent months regaining movement in his left leg. He later returned to work and led Giffords’s district office as she continued her recovery in Texas.

Giffords announced her resignation in January and signaled that she wanted Barber to succeed her. Fulfilling those wishes, Barber won a special election last week by defeating Republican Jesse Kelly, an Iraq war veteran who ran against Giffords in 2010.

Giffords endorsed Barber’s candidacy and played only a minor role during the campaign, appearing at one campaign rally, in a Barber campaign mailer and in a super PAC ad that also showed Kelly criticizing her during his run against her in 2010.

As he stepped onto the floor of the House shortly before 2 p.m., several of Barber’s new colleagues from both parties greeted him with handshakes and hugs. Before the oath ceremony, Barber sat in the front row of the Democratic side of the House next to three of his grandchildren and House Minority Leader Nancy Pelosi (D-Calif.) and in front of Rep. John Dingell (D-Mich.), the chamber’s longest-serving member. Rep. Debbie Wasserman Schultz (D-Fla.), a close friend of Giffords, also sat behind Barber and appeared to have tears in her eyes during the ceremony.

“The fact that we are gathered today is a tribute to our fine colleague Gabby Giffords,” Rep. Ed Pastor (D-Ariz.) said as he formally introduced Barber to his new colleagues. Rep. Jeff Flake (R-Ariz.) added “nobody would wish for the circumstances” that brought Barber to Washington but added that his GOP colleagues wished him well.

In brief remarks, Barber thanked his wife, Nancy, noting that the couple will celebrate their 45th wedding anniversary on Wednesday. Those comments triggered a sustained standing ovation from lawmakers.

Acknowledging his former boss, Barber said, “Gabby, southern Arizona misses you, and we cannot wait to have you home.”

Barber, 66, is one of dozens of lawmakers who previously served as congressional staffers — a group that includes Rep. Paul Ryan (R-Wis.) and Sens. Mark Warner (D-Va.) and Mark Kirk (R-Ill). He is also one of a smaller clutch of congressmen who succeeded their former bosses, including Majority Whip Kevin McCarthy (R-Calif.), who replaced former Rep. Bill Thomas (R-Calif.), and Jo Bonner (R-Ala.), who once worked for former Rep. Sonny Callahan (R-Ala.).

Despite last week’s win, Barber faces reelection in November for a full two-year term. A GOP primary to pick his challenger will be held in late August.

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This post has been updated since it was first published.