A staggering total of 15,266 former staff responded to the "Your NHS Needs You" recruitment drive, according to the Department of Health and Social Care (DHSC).
This includes 5,117 doctors, 5,605 nurses and midwives and 3,686 pharmacists and other professionals.
The DHSC also said that next week, 5,750 final year medics and 17,000 final year nursing students in England will be asked to consider starting frontline placements.
It said young recruits would receive "appropriate support" in their new roles.
In the last year the number of nurses in the NHS has increased by 9,398 to 289,810, while the number of doctors has risen by 5,188 over the same period, the DHSC said.
It comes as more than 670,000 people had signed up for the NHS volunteer programme in 48 hours, prompting the Government to increase the target to 750,000.
Volunteers have been asked to provide telephone support to those left anxious and isolated, community support such as delivering shopping and medication, and transport for those who need to be moved.
Health Secretary Matt Hancock said: "I'm so proud that since our rallying call, 38,000 more people will join or return to the NHS as health and care workers on the frontline fighting Covid-19.
"Our NHS is facing an unprecedented challenge and I pay tribute to each and every one of them helping battle this virus.
"The entire country is grateful but we must help them too. That's why we are telling everyone to stay at home, protect the NHS and save lives."