Carberry, who joined the club towards the end of the 2017 season, replaces Mark Cosgrove as captain and will lead in all three formats. Leicestershire failed to win a Championship match in 2017 and finished bottom of the division two table.
While Carberry may feel he has some questions to answer about his own form - he averaged just 17.42 in the County Championship for Hampshire and Leicestershire in 2017 - he has vast experience from a career that has seen him represent England in all three formats and win four limited-overs trophies with Hampshire.
Despite his own health problems and advancing years (he is 37), Carberry has also remained impressively fit and is seen as the sort of role-model cricketer than can inspire Leicestershire's younger players.
Cosgrove, who was easily the club's highest run-scorer in the Championship in 2017, will continue at Leicestershire as a player.
Smith, meanwhile, returns to a club he represented on-loan in 2008. Having seen an impressive career as an all-rounder curtailed by injury - Smith was part of the Lancashire side that won the County Championship in 2011 and was appointed the club captain ahead of the 2015 season - he has had coaching spells with Lancashire's academy, Lancashire Thunder and England Women. He is 32.
The appointment completes a transformation of the club's coaching staff over recent months which has also seen Paul Nixon appointed as head coach, Matt Mason appointed as bowling coach and John Sadler appointed as assistant coach.
"This is an exciting opportunity for me at Leicestershire and it is great to be working alongside Nico [Paul Nixon], John Sadler, Matt Mason and all of the coaching staff," Smith said. "I enjoyed my time here as a player alongside Nico so it was an easy decision to make. I'm really looking forward to being part of a fresh coaching team at the Foxes and can't wait to get started."
"Tom is a brilliant bloke who I had the pleasure of playing alongside here," Nixon said. "He was a top-class cricketer who was highly skilled across all formats. Tom was named as captain of Lancashire at a young age which shows his pedigree.
"He has since upskilled his coaching CV with work at Lancashire both in the men's and women's game and has also been working with the England Women team. We're delighted to have Tom on board with us."