Anderson (GMB, p 1698) names no parents for Ralph Smith, but points out he was likely from Hingham, England. Until more recent (than 1995) research can confirm it, we are detaching him from the 6 Apr 1612 birthdate and specific parents John Smith/John Smythe and Grace Unknown/Grace Margaret.
Anderson (GMB, p 1698) indicates only one spouse, Grace _____:
"Most sources claim that Ralph Smith had two wives, and the children were by the first. There are also claims that his wife Grace was widow of Thomas Hatch of Barnstable, but his widow had apparently died by 1662. The only wife seen in the records for Ralph is Grace.
Therefore until more recent (than 1995) research indicates otherwise, Elizabeth Hobart is being detached as his spouse and mother of his children. "The record of the first wife of Mr. Smith has not been found. She was probably the mother of his children. His second wife Grace ___, was the widow of Thomas Hatch."
Ralph Smith was born by 1616 probably in Hingham, Norfolk, England (assuming he came over as a servant, and was 21 at time of his trial admission by the town of Charlestown).
He emigrated in 1633. "1633 Also Ralph Smith came from Old Hingham and lived in this town."
Sailed out of Yarmouth, Norfolk County, England, the first week in May 1633 on the Elizabeth Bonaventure (EB), and arrived in Massachusetts Bay (Charlestown/Boston) on June 15, 1633, from the book "Planters of the Commonwealth" by Charles E. Banks, that gives the name of the ship as Elizabeth Bonaventure. (Anderson does not name a ship; see GMB, p 1697)
He married before 1640 (and likely in Hingham, Massachusetts, but no record found) Grace _____, who survived him. They must have been admitted to Hingham, Massachusetts church by 1641 since baptisms of their children start there and then.
He took the oath of fidelity at Eastham in 1657.
He was chosen constable of Eastham on 6 Jun 1660. but he did not hold onto this office long.
"On 7 May 1661, 'Ralph Smith, for lying in and about the neglect of his duty, about a warrant directed to him, and concerning the seeing or not seeing a whale, and other misorderly carriages tending to disturbance in the town of Eastham, was fined twenty shillings. [PCR 3:213]
He continued to have difficulties in dealing with his fellow man. On 3 Mar 1662/3 "Ralph Smith, of Eastham, for breaking the peace in striking of Wiliam Walker, is fined 3s 4d.". In May 1665 "Ralph Smith, of Eastham, was fined for telling of a lie, 10s"  More troubles for Ralph can be found in PCR 4:175, 5:31, 7:69, 149)
He died 14 September 1685 (from inventory of his estate).
His descendants erected a monument in his honor:
"TO THE MEMORY OF RALPH SMITH - BORN AT HINGHAM ENGLAND 1610 - LEADING FIGURE IN FOUNDING HINGHAM, MASSACHUSETTS 1633 - REMOVED TO EASTHAM ABOUT 1654.
DIED THERE 1685 - A PIONEER OF DISTINCTION. ERECTED BY THE ASSOCIATION OF DESCENDANTS OF RALPH SMITH, JUNE 1946."
In 1872 Thomas Smyth published a thumbnail sketch of the family of Ralph Smith which omitted all notice of his daughters [ NEHGR 26:190-97].
Colket, Jr., Meredith B. 1912-. Founders of Early American Families: Emigrants From Europe, 1607-1657, Revised Edition. Cleveland: General Court of the Order of Founders and Patriots of America : distributed by Founders Project, 1985. Text located at the New England Historical and Genealogical Society library. Page 289.
It may be possible to confirm family relationships with Ralph by comparing test results with other carriers of his Y-chromosome or his mother's mitochondrial DNA.
However, there are no known yDNA or mtDNA test-takers in his direct paternal or maternal line.
It is likely that these autosomal DNA test-takers will share DNA with Ralph:
What Martha posted is an image of a profile about Ralph Smith from Ancestry's North America, Family Histories collection. It cites as its sources: Ralph Smyth of Hingham and Eastham (by Dwight Smith, 1913); and NEHGR 2:251; 15:25. These last two are already cited on the profile, but the other may be worth looking at.
Sources: Ralph Smyth of Hingham and Eastham by Dwight Smith, 1913. New England Historical and Genealogical Register, vol.2, p251; vol. 15, p25, North America, Family Histories, 1500-2000 for Ralph Smith
Martha (and others), please note that the linked-to page offers no sources other than online trees for the claims it makes. Typically, we follow Anderson until more recently published research shows other results.