Oliver Hawkins put Dagenham ahead after 32 minutes when he headed in Jordan Maguire-Drew's cross, but the hosts levelled just three minutes later through Michael Cheek.
Akinola's penalty on the stroke of half-time put Braintree ahead at the break but two minutes after the interval the Daggers were awarded a spot-kick of their own and, while Hawkins' effort was saved, Maguire-Drew smashed home the rebound.
The away side had Scott Doe sent off for a second booking, and Braintree took advantage as Akinola scored his second.
Braintree's Manny Parry was also given his marching orders but Dagenham were reduced to nine men when Magnus Okuonghae went off injured with all three substitutions made.
Report supplied by the Press Association.
Match ends, Braintree Town 3, Dagenham and Redbridge 2.
Second Half ends, Braintree Town 3, Dagenham and Redbridge 2.
Substitution, Braintree Town. Zak Jules replaces Ian Gayle.
Substitution, Braintree Town. Harry Lee replaces Reece Hall-Johnson.
Ebou Adams (Braintree Town) is shown the red card.
Substitution, Dagenham and Redbridge. Paul Benson replaces Jordan Maguire-Drew.
Substitution, Dagenham and Redbridge. Scott Heard replaces Sam Ling.
Goal!  Braintree Town 3, Dagenham and Redbridge 2. Simeon Akinola (Braintree Town).
Second yellow card to Scott Doe (Dagenham and Redbridge) for a bad foul.
Reece Hall-Johnson (Braintree Town) is shown the yellow card.
Substitution, Dagenham and Redbridge. Magnus Okuonghae replaces Tyrique Hyde.
Goal!  Braintree Town 2, Dagenham and Redbridge 2. Jordan Maguire-Drew (Dagenham and Redbridge).
Second Half begins Braintree Town 2, Dagenham and Redbridge 1.
First Half ends, Braintree Town 2, Dagenham and Redbridge 1.
Goal!  Braintree Town 2, Dagenham and Redbridge 1. Simeon Akinola (Braintree Town) converts the penalty with a.
Sam Ling (Dagenham and Redbridge) is shown the yellow card.
Goal!  Braintree Town 1, Dagenham and Redbridge 1. Michael Cheek (Braintree Town).
Goal!  Braintree Town 0, Dagenham and Redbridge 1. Oliver Hawkins (Dagenham and Redbridge).
Ebou Adams (Braintree Town) is shown the yellow card.
First Half begins.
Lineups are announced and players are warming up.
Simeon Akinola scored twice as Braintree beat promotion-chasing Dagenham 3-2 in a thrilling National League game.